Selective Hydrogenation Using a Flow Index

ABSTRACT

A process includes hydrogenating, in a reaction zone, a highly unsaturated hydrocarbon received from a hydrocarbon stream to yield a product having an unsaturated hydrocarbon, the hydrogenating step occurring in the presence of a hydrogenation catalyst which has a selectivity for conversion of the highly unsaturated hydrocarbon to the unsaturated hydrocarbon of about 90 mol % or greater based on the moles of the highly unsaturated hydrocarbon which are converted to the product, the hydrogenating step occurring in a reaction zone under conditions which include a flow index (I F ) in a range of about 0.09 to about 35, wherein the I F  is defined as: 
     
       
         
           
             
               
                 I 
                 F 
               
               = 
               
                 
                   F 
                   × 
                   
                     [ 
                     CO 
                     ] 
                   
                 
                 V 
               
             
             , 
           
         
       
     
     wherein F is the flow rate of the hydrocarbon stream into the reaction zone in units of kg/h, [CO] is the concentration of carbon monoxide in the hydrocarbon stream in units of mol %, and V is the volume of the reaction zone in units of ft 3 .

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a divisional of and claims priority to U.S. patentapplication Ser. No. 15/671,597 and published as U.S. Patent ApplicationPublication No. US2017/0349507, and entitled “Selective HydrogenationUsing a Flow Index,” and U.S. patent application Ser. No. 14/942,816filed Nov. 16, 2015 and published as U.S. Patent Application PublicationNo. US2017/0137346 A1, now U.S. Pat. No. 9,758,446, and entitled“Selective Hydrogenation Using a Flow Index,” which is incorporated byreference herein in its entirety.

STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT

Not applicable.

REFERENCE TO A MICROFICHE APPENDIX

Not applicable.

FIELD

The present disclosure relates to the production of an unsaturatedhydrocarbon, and more particularly to a hydrogenation of compounds usinghighly selective catalyst.

BACKGROUND

Unsaturated hydrocarbons such as ethylene and propylene are oftenemployed as feedstocks in preparing value added chemicals and polymers.Unsaturated hydrocarbons can be produced by pyrolysis or cracking ofhydrocarbons including hydrocarbons derived from coal, oil, gas,synthetic crude, naphthas, natural gas liquids, raffinate, refinerygases, ethane, propane, butane, and the like. Unsaturated hydrocarbonsproducts produced in these manners usually contain highly unsaturatedhydrocarbons such as acetylenes and diolefins that adversely affect theproduction of subsequent chemicals and polymers. Thus, to form anunsaturated hydrocarbon product such as a polymer grade monoolefin, theamount of acetylenes and diolefins in the monoolefin stream is typicallyreduced.

One technique commonly used to reduce the amount of acetylenes anddiolefins in an unsaturated hydrocarbon stream primarily comprisingmonoolefins involves hydrogenating the acetylenes and diolefins tomonoolefins. This process is selective in that hydrogenation of amonoolefin and a highly unsaturated hydrocarbon to the saturatedhydrocarbon is minimized. For example, the hydrogenation of ethylene oracetylene to ethane is minimized.

One challenge to the selective hydrogenation process is the potentialfor a runaway reaction which is uncontrolled hydrogenation of ethyleneto ethane. One methodology to minimize runaway reactions is to use ahighly selective hydrogenation catalyst. The availability of highlyselective hydrogenation catalysts, however, has brought about otherchallenges for converting a highly unsaturated hydrocarbon to anunsaturated hydrocarbon.

SUMMARY

Disclosed herein is a process comprising hydrogenating, in a reactionzone, a highly unsaturated hydrocarbon received from a hydrocarbonstream to yield a product comprising an unsaturated hydrocarbon, whereinthe hydrogenating step occurs in the presence of a hydrogenationcatalyst which has a selectivity for conversion of the highlyunsaturated hydrocarbon to the unsaturated hydrocarbon of about 90 mol %or greater based on the moles of the highly unsaturated hydrocarbonwhich are converted to the product, wherein the hydrogenating step inthe reaction zone occurs under conditions comprising a flow index(I_(F)) in a range of from about 0.09 to about 35; alternatively, fromabout 0.27 to about 25; alternatively, from about a 0.4 to about 20;alternatively, from about 1.0 to about 5.6, wherein the I_(F) is definedas:

${I_{F} = \frac{F \times \lbrack{CO}\rbrack}{V}},$

wherein F is the flow rate of the hydrocarbon stream into the reactionzone in units of kg/h, [CO] is the concentration of carbon monoxide inthe hydrocarbon stream in units of mol %, and V is the volume of thereaction zone in units of ft³.

Also disclosed herein is a system comprising a hydrocarbon streamcomprising a highly unsaturated hydrocarbon and carbon monoxide, and areaction zone receiving the hydrocarbon stream, wherein the reactionzone contains at least one hydrogenation catalyst, wherein the highlyunsaturated hydrocarbon is hydrogenated in the reaction zone to yield aproduct comprising an unsaturated hydrocarbon, wherein the at least onehydrogenation catalyst has a selectivity for conversion of the highlyunsaturated hydrocarbon to the unsaturated hydrocarbon of about 90 mol %or greater based on the moles of the highly unsaturated hydrocarbonwhich are converted to the product, wherein the reaction zone cancomprise a flow index (I_(F)) in a range of from about 0.09 to about 35;alternatively, from about 0.27 to about 25; alternatively, from about0.4 to about 20; alternatively, from about 1.0 to about 5.6, wherein theI_(F) is defined as:

${I_{F} = \frac{F \times \lbrack{CO}\rbrack}{V}},$

wherein F is the flow rate of the hydrocarbon stream into the reactionzone in units of kg/h, [CO] is the concentration of carbon monoxide inthe hydrocarbon stream in units of mol %, and V is the volume of theportion of the reaction zone in units of ft³.

Further disclosed herein is a system comprising a furnace comprising atleast one tube comprising a co-production metal, a cracked gas streamcomprising a highly unsaturated hydrocarbon, a saturated hydrocarbon,and carbon monoxide flowing from the at least one tube, a fractionationzone comprising a deethanizer or a depropanizer, wherein thefractionation zone fractionates the cracked gas stream into an overheadproduct and a bottoms product, wherein the overhead product can comprisethe highly unsaturated hydrocarbon, carbon monoxide, and about 90 mol %or greater of the saturated hydrocarbon contained in the cracked gasstream, a hydrocarbon stream comprising the overhead product flowingfrom the fractionation zone, and a reaction zone receiving thehydrocarbon stream, wherein the reaction zone can comprise at least onehydrogenation catalyst, wherein, in the reaction zone, the highlyunsaturated hydrocarbon is hydrogenated to yield a product comprising anunsaturated hydrocarbon in the reaction zone, wherein the reaction zonecan comprise a flow index (I_(F)) in a range of from about 0.09 to about35; alternatively, from about 0.27 to about 25; alternatively, fromabout 0.4 to about 20; alternatively, from about 1.0 to about 5.6,wherein the I_(F) is defined as:

${I_{F} = \frac{F \times \lbrack{CO}\rbrack}{V}},$

wherein F is the flow rate of the hydrocarbon stream into the reactionzone in units of kg/h, [CO] is the concentration of carbon monoxide inthe hydrocarbon stream in units of mol %, and V is the volume of theportion of the reaction zone in units of ft³.

Further disclosed herein is a process comprising cracking a feed streamto produce a cracked gas stream comprising acetylene, ethylene, ethane,methane, hydrogen, carbon monoxide, and C₃ ⁺ components, fractionatingthe cracked gas stream into a C₂ ⁻ stream and a C₃ ⁺ stream, wherein theC₂ ⁻ stream can comprise acetylene, ethylene, ethane, methane, hydrogen,and carbon monoxide, wherein the C₃ ⁻ stream can comprise the C₃ ⁻components, hydrogenating at least a portion of the acetylene of the C₂⁻ stream in the presence of a hydrogenation catalyst to yield a productcomprising ethylene, wherein the hydrogenation catalyst has aselectivity for conversion of acetylene to ethylene of about 90 mol % orgreater based on the moles of acetylene which are converted to theproduct, wherein the hydrogenating at least a portion of the acetyleneoccurs in a reaction zone under conditions comprising a flow index(I_(F)) in a range of from about 0.09 to about 35; alternatively, fromabout 0.27 to about 25; alternatively, from about 0.4 to about 20;alternatively, from about 1.0 to about 5.6, wherein the I_(F) is definedas:

${I_{F} = \frac{F \times \lbrack{CO}\rbrack}{V}},$

wherein F is the flow rate of the C₂ ⁻ stream into the reaction zone inunits of kg/h, [CO] is the concentration of carbon monoxide in the C₂ ⁻stream in units of mol %, and V is the volume of the portion of thereaction zone in units of ft³, removing ethylene from the product, andpolymerizing ethylene into one or more polymer products.

Further disclosed herein is a process comprising providing a hydrocarbonstream comprising a highly unsaturated hydrocarbon and carbon monoxideto a reaction zone comprising a hydrogenation catalyst, andhydrogenating, in the reaction zone, the highly unsaturated hydrocarbonto yield a product comprising an unsaturated hydrocarbon, wherein thehydrogenation catalyst has a selectivity for conversion of the highlyunsaturated hydrocarbon to the unsaturated hydrocarbon of about 90 mol %or greater based on moles of the highly unsaturated hydrocarbon whichare converted to the product, wherein the hydrogenating in the reactionzone occurs under conditions comprising a flow index (I_(F)) in a rangeof from about 0.09 to about 35; alternatively, from about 0.27 to about25; alternatively, from about 0.4 to about 20; alternatively, from about1.0 to about 5.6, wherein the I_(F) is defined as:

${I_{F} = \frac{F \times \lbrack{CO}\rbrack}{V}},$

wherein F is the flow rate of the hydrocarbon stream into the reactionzone in units of kg/h, [CO] is the concentration of carbon monoxide inthe hydrocarbon stream in units of mol %, and V is the volume of theportion of the reaction zone in units of ft³.

BRIEF DESCRIPTION OF THE DRAWINGS

For a more complete understanding of the present disclosure and theadvantages thereof, reference is now made to the following briefdescription, taken in connection with the accompanying drawings anddetailed description, wherein like reference numerals represent likeparts.

FIG. 1 illustrates embodiments of the disclosed system and process.

FIG. 2 illustrates other embodiments of the disclosed system andprocess.

DETAILED DESCRIPTION

Embodiments of systems and processes for selective hydrogenation using aflow index, I_(F), are disclosed herein. It should be understood at theoutset that although an illustrative implementation of one or moreembodiments are provided below, the disclosed systems and processes canbe implemented using any number of techniques, whether currently knownor in existence. The disclosure should in no way be limited to theillustrative implementations, drawings, and techniques illustratedbelow, including the exemplary designs and implementations illustratedand described herein, but can be modified within the scope of theappended claims along with their full scope of equivalents.

As used herein, a “highly unsaturated hydrocarbon” is defined as ahydrocarbon containing a triple bond, two conjugated carbon-carbondouble bonds, or two cumulative carbon-carbon double bonds. Examples ofa highly unsaturated hydrocarbon include, but are not limited to,alkynes such as acetylene, methylacetylene (also referred to aspropyne), and butynes; diolefins such as propadiene, butadienes,pentadienes (including isoprene), the like, and combinations thereof.

As used herein, an “unsaturated hydrocarbon” is defined as a hydrocarboncontaining an isolated carbon-carbon double bond. Examples of anunsaturated hydrocarbon include, but are not limited to, monoolefinssuch as ethylene, propylene, butenes, pentenes, the like, andcombinations thereof.

As used herein, a “saturated hydrocarbon” is defined as a hydrocarboncontaining no carbon-to-carbon double bonds or carbon-to-carbon triplebonds. Examples of a saturated hydrocarbon include, but are not limitedto, methane, ethane, propane, butanes, pentanes, the like, andcombinations thereof.

FIG. 1 shows embodiments of the disclosed system 100 can comprise ahydrocarbon stream 24 which flows to a reaction zone 30 (for example thereaction zone 30 receives the hydrocarbon stream 24). Generally, ahighly unsaturated hydrocarbon fed to the reaction zone 30 viahydrocarbon stream 24 is hydrogenated in the reaction zone 30 in thepresence of a hydrogenation catalyst and in the presence of hydrogen. Inembodiments, the reaction zone 30 can comprise a first stage 31, asecond stage 35 connected in series with the first stage 31, and a firsteffluent stream 33 via which a reaction effluent flows from the firststage 31 of the reaction zone 30 to the second stage 35 of the reactionzone 30. A highly unsaturated hydrocarbon fed to the reaction zone 30via hydrocarbon stream 24 is hydrogenated in the first stage 31, andunconverted or unreacted highly unsaturated hydrocarbon flow in thefirst effluent stream 33 to the second stage 35, wherein the unconvertedor unreacted highly unsaturated hydrocarbon is hydrogenated in thesecond stage 35. The product(s) of the first stage 31 and second stage35 leave the reaction zone 30 via the second effluent stream 36. Toaccomplish hydrogenation, each of the first stage 31 and second stage 35can comprise one or more hydrogenation catalysts (embodiments which aredescribed herein). In an embodiment, the first stage 31, the secondstage 35, or both can belong to an acetylene removal unit (ARU) of anunsaturated hydrocarbon production plant, discussed in more detailherein.

In embodiments, the reaction zone 30 can operate at conditions (forexample gas phase, liquid phase, or both) effective to hydrogenate ahighly unsaturated hydrocarbon to an unsaturated hydrocarbon uponcontacting the disclosed hydrogenation catalyst in the presence ofhydrogen. In embodiments having reaction zones with multiple stages (forexample reaction zone 30 of FIG. 1), each of the first stage 31; thesecond stage 35; or both stages of the reaction zone 30 can operate atconditions (for example gas phase, liquid phase, or both) effective tohydrogenate the highly unsaturated hydrocarbon to an unsaturatedhydrocarbon upon contacting the disclosed hydrogenation catalyst in thepresence of the hydrogen.

In embodiments, the first stage 31 of the reaction zone 30 can be afirst reactor, and the second stage 35 of the reaction zone 30 can be asecond reactor. In such embodiments, the first reactor can be separatefrom and in series with the second reactor. In such embodiments, thefirst effluent stream 33 can comprise equipment (for example pipes,valves, pumps, heat exchangers, instrumentation, other equipment knownin the art with the aid of this disclosure, or combinations thereof)which fluidly connects the first reactor and the second reactor suchthat a first reaction effluent can flow from the first stage 31 of thereaction zone 30 to the second stage 35 of the reaction zone 30 via thefirst effluent stream 33. For example, a heat exchanger can be placedbetween the first stage 31 of the reaction zone 30 and the second stage35 of the reaction zone 30 to add or remove heat to achieve thereactions disclosed herein. In embodiments, no heat is added to thefirst effluent stream 33 between the first stage 31 and the second stage35. In embodiments, a first temperature of the first effluent stream 33flows into the second stage 35 (or the second reactor) is the same as orlower than a second temperature of the first effluent stream 33 as thefirst effluent stream 33 exits from the first stage 31 (or the firstreactor).

In alternative embodiments, the first stage 31 of the reaction zone 30can be contained within the same vessel as the second stage 35 of thereaction zone 30 (for example first stage 31 and second stage 35 arecatalyst beds within the same reactor). In such embodiments, the firsteffluent stream 33 can comprise equipment (for example pipe, valves,baffles, packing, screens, other internal equipment known in the artwith the aid of this disclosure, or combinations thereof) which fluidlyconnects the first stage 31 of the reaction zone 30 and the second stage35 of the reaction zone 30 such that the reaction medium can flow fromthe first stage 31 of the reaction zone 30 to the second stage 35 of thereaction zone 30 (for example the first stage 31 of the reaction zone 30and the second stage 35 of the reaction zone 30 are fluidly connected inseries).

In additional or alternative embodiments, the first stage 31 of thereaction zone 30, the second stage 35 of the reaction zone 30, or bothcan represent a plurality of reactors. The plurality of reactors canoptionally be separated by a means to remove add or remove heat producedby the reaction. The plurality of reactors can optionally be separatedby a means to control inlet and effluent flows from reactors or heatremoval means allowing for individual or alternatively groups ofreactors within the plurality of reactors to be regenerated. Theplurality of reactors can optionally be separated by equipment (forexample pipe, valves, pumps, heat exchangers, instrumentation, otherequipment known in the art with the aid of this disclosure, orcombinations thereof).

In the various embodiments of the reaction zone 30, at least oneembodiment of the hydrogenation catalyst can be arranged in any suitableconfiguration within the first stage 31 of the reaction zone 30; thesecond stage 35; or both stages of the reaction zone 30, such as a fixedcatalyst bed, a fluidized bed, or both.

Designated with dashed lines in FIG. 1, the system 100 can comprise afurnace 10 comprising one or more metal tubes through which thecomponents of the feed stream 12 flow. The tubes of the furnace 10 areconfigured to thermally crack at least one of the hydrocarbon componentsof the feed stream 12 (for example comprising a raw gas, natural gasliquids, raffinate, oil, coal oil, petroleum naphtha, a refinery streamcomprising a crackable hydrocarbon, and other feed sources known in theart with the aid of this disclosure).

The product of the furnaces is a cracked gas stream 14. In embodiments,the cracked gas stream 14 can comprise a highly unsaturated hydrocarbon,an unsaturated hydrocarbon, hydrogen, carbon monoxide, a saturatedhydrocarbon, or combinations thereof. In embodiments, the cracked gasstream 14 may can comprise from about 10 ppmw to about 20,000 ppmw of ahighly unsaturated hydrocarbon based on the total weight of allhydrocarbons in the cracked gas stream 14.

In embodiments, the furnace 10 can comprise an insulated box and one ormore burners. The components of the feed stream 12 can be heated (forexample by burning of a fuel in the burner) as the components flowthrough the one or more tubes in the furnace 10 such that at least onecomponent of the feed stream 12 is thermally cracked, for example, toproduce an unsaturated hydrocarbon (for example ethylene, propylene, orboth). At least one tube of the furnace 10 can have at least a portionwhich can comprise a co-production metal. In embodiments, theco-production metal is a coating on the interior of the one or moretubes (for example steel tubes). In embodiments, the co-production metalcan comprise chromium, aluminum, or both. The chromium can be added tothe base metal (for example steel) and migrate to form a coating on theinterior of the tubes, the chromium can be coated on the interior of thetubes (for example steel tubes), or both. The aluminum can be added tothe base metal (for example steel) and migrate to form a coating on theinterior of the tubes, the aluminum can be coated on the interior of thetubes (for example steel tubes), or both. For example, one or more steeltubes can be aluminized with a coating of aluminum by adding aluminum tothe bulk of the steel. When the one or more tubes are put into service,the aluminum migrates to the surface of the tubes to form a thinaluminized coating.

Designated with dashed lines in FIG. 1, embodiments of the system 100can include a fractionation zone 20 which is upstream of the reactionzone 30. In embodiments, the fractionation zone 20 can comprise a vesselhaving internal components such as distillation trays (for examplesieve-type, dual-flow, bubble cap, donut), packing materials, or both.The fractionation zone 20 can operate at conditions which provide forthe fractionation of the cracked gas stream 14 according to theembodiments disclosed herein.

In embodiments, the fractionation zone 20 can comprise a deethanizer(the system 100 is in a frontend deethanizer configuration), adepropanizer (the system 100 is in a frontend depropanizerconfiguration), or both a demethanizer and a deethanizer (the system 100is in a backend configuration).

The fractionation zone 20 comprising a deethanizer can receive a crackedgas stream 14 from an unsaturated hydrocarbon production process (forexample from the furnace 10) and fractionate the cracked gas stream 14into an overhead product (for example a C₂ ⁻ stream) and a bottomsproduct (for example a C₃ ⁺ stream). In such embodiments, the crackedgas stream 14 can comprise hydrogen, carbon monoxide, propane, ethane,methane, methylacetylene, propadiene, acetylene, ethylene, propylene, C₄⁺ components (for example C₄ hydrocarbons and heavier), or combinationsthereof. The overhead product can be an ethane-rich stream; the overheadproduct can comprise about 90 mol % or greater of the ethane containedin the cracked gas stream 14; the overhead product can comprise C₂ ⁻components such as acetylene, ethylene, ethane, methane, hydrogen,carbon monoxide, or combinations thereof; or combinations thereof. Inembodiments, the overhead product can be fed to the first stage 31 ofreaction zone 30, the second stage 35 of reaction zone 30, or both, viaone or more streams such as hydrocarbon stream 24. The bottoms product(for example comprising C₃ ⁺ components such as propane,methylacetylene, propadiene, propylene, or combinations thereof) canflow from the fractionation zone 20 via stream 22.

The fractionation zone 20 comprising a depropanizer can receive acracked gas stream 14 from an unsaturated hydrocarbon production process(for example from the furnace 10) and fractionate the cracked gas stream14 into an overhead product (for example a C₃ ⁻ stream) and a bottomsproduct (for example a C₄ ⁺ stream). In such embodiments, the crackedgas stream 14 can comprise hydrogen, carbon monoxide, propane, ethane,methane, methylacetylene, propadiene, acetylene, ethylene, propylene, C₄⁺ components (for example C₄ hydrocarbons and heavier), or combinationsthereof. The overhead product can comprise about 90 mol % or greater ofthe ethane or propane contained in the cracked gas stream 14. Theoverhead product (for example comprising C₃ ⁻ components such ashydrogen, carbon monoxide, propane, ethane, methane, methylacetylene,propadiene, acetylene, ethylene, propylene, or combinations thereof) canbe fed to the first stage 31 of reaction zone 30, the second stage 35 ofreaction zone 30, or both, via one or more streams such as hydrocarbonstream 24. The bottoms product (for example comprising C₄ ⁺ componentssuch as C₄ hydrocarbons and heavier) can flow from the fractionationzone 20 via stream 22.

In embodiments, the fractionation zone 20 can comprise a demethanizerand a deethanizer. In such an embodiment, the demethanizer can receive acracked gas stream 14 from an unsaturated hydrocarbon production process(for example from the furnace 10) and fractionate the cracked gas stream14 into an overhead product (for example a methane-rich stream) and abottoms product (for example a C₂ ⁺ stream). In such embodiments, thecracked gas stream 14 to the demethanizer can comprise hydrogen, carbonmonoxide, propane, ethane, methane, methylacetylene, propadiene,acetylene, ethylene, propylene, C₄ ⁺ components (for example C₄hydrocarbons and heavier), or combinations thereof. The overhead productof the demethanizer can comprise methane, hydrogen, and carbon monoxide;can comprise about 90 mol % or greater of the methane contained in thecracked gas stream 14; or both. The bottoms product of the demethanizercan comprise about 90 mol % or greater of the ethane contained in thecracked gas stream 14; the bottoms product of the demethanizer cancomprise C₂ ⁺ components (for example ethane, acetylene, ethylene,methylacetylene, propadiene, propylene, propane, or combinationsthereof); or combinations thereof. The bottoms product of thedemethanizer then flows to the deethanizer where the deethanizerfractionates the demethanizer bottoms product into an overhead product(for example a C₂ ⁻ stream) and a bottoms product (for example a C₃ ⁺stream). The overhead product of the deethanizer can be an ethane-richstream; the overhead product of the deethanizer can comprise about 90mol % or greater of the ethane contained in the demethanizer bottomsproduct; the overhead product can comprise C₂ ⁻ components such asacetylene, ethylene, ethane, methane, or combinations thereof; orcombinations thereof. In embodiments, the overhead product of thedeethanizer can be fed to the first stage 31 of reaction zone 30, thesecond stage 35 of reaction zone 30, or both, via one or more streamssuch as hydrocarbon stream 24. The bottoms product of the deethanizer(for example comprising C₃ ⁺ components such as propane,methylacetylene, propadiene, propylene, or combinations thereof) canflow from the fractionation zone 20 via stream 22.

It is understood that first stage 31 and second stage 35 of the reactionzone 30, and likewise the hydrogenation catalysts disclosed herein, arenot limited to use in raw gas, frontend deethanizer, frontenddepropanizer, or backend configurations, and can be used in any processwherein a highly unsaturated hydrocarbon contained within thehydrocarbon stream 24 are hydrogenated to an unsaturated hydrocarbon.

In an embodiment, the first stage 31, the second stage 35, or both canbelong to an acetylene removal unit (ARU) of an unsaturated hydrocarbonproduction plant in a frontend deethanizer configuration, a frontenddepropanizer configuration, or a backend configuration (described inmore detail below).

In embodiments, the temperature within the reaction zone 30 (for examplea portion thereof, the first stage 31, the second stage 35, orcombinations thereof) can be in the range of from about 5° C. to about300° C.; alternatively, from about 10° C. to about 250° C.;alternatively, from about 15° C. to about 200° C. In some embodiments,the pressure within the reaction zone 30 (for example a portion thereof,the first stage 31, the second stage 35, or combinations thereof) can bein the range of from about 15 (204 kPa) to about 2,000 (13,890 kPa)pounds per square inch gauge (psig); alternatively, from about 50 psig(446 kPa) to about 1,500 psig (10,443 kPa); alternatively, from about100 psig (790 kPa) to about 1,000 psig (6,996 kPa).

In embodiments, a temperature of the first stage 31 of the reaction zone30 can be the same or different than a temperature of the second stage35 of the reaction zone 30. Likewise, a pressure of the first stage 31of the reaction zone 30 can be the same or different than a pressure ofthe second stage 35 of the reaction zone 30.

In embodiments, the reaction zone 30 (for example at least a portion ofreaction zone 30, the first stage 31, the second stage 35, etc.) canhave a flow index (I_(F)) defined by the equation below:

$I_{F} = \frac{F \times \lbrack{CO}\rbrack}{V}$

wherein F is the flow rate of the hydrocarbon stream 24 into thereaction zone 30 in units of kg/h, [CO] is the concentration of carbonmonoxide in the hydrocarbon stream 24 in units of mol %, and V is thevolume of the reaction zone 30 (for example at least a portion of thereaction zone 30, the first stage 31, the second stage 35, etc.) inunits of ft³. In embodiments, the flow index (I_(F)) can comprise valuesin a range of from about 0.09 to about 35; alternatively, from about0.27 to about 25; alternatively, from about 0.4 to about 20;alternatively, from about 1.0 to about 5.6.

In embodiments, at least a portion of the reaction zone can comprise 0%to 100% of the reaction zone 30 (for example comprising a single stagereaction zone). In embodiments having one or more multi-stage reactionzones, at least a portion of the reaction zone can comprise 0% to 100%of the first stage 31 of the reaction zone 30, 0% to 100% of the secondstage 35 of the reaction zone 30, 0% to 100% of any other stage, orcombinations thereof.

The flow index (I_(F)) values disclosed herein are attainable for thehydrogenation of a highly unsaturated hydrocarbon to an unsaturatedhydrocarbon on a commercial scale using an embodiment of thehydrogenation catalyst disclosed herein. Table 1 shows some exampleoperating conditions which achieve the flow index (I_(F)) disclosedherein:

TABLE 1 Volume Flow Rate [CO] Flow Index (I_(F)) (ft3) (kg/hr) (mol %)[(kg mol %)/(hr ft³)] 1 500 65,000 0.04 5.2 2 500 85,000 0.15 25 3 1,000225,000 0.012 2.7 4 1,000 275,000 0.02 5.5 5 2,000 77,000 0.007 0.27 62,000 325,000 0.012 1.95 7 3,000 425,000 0.008 1.1 8 3,000 500,000 0.0254.2

As can be seen in Table 1, various reactor volumes, flow rates, andconcentrations of carbon monoxide can be used which achieve the flowindex disclosed herein. Reaction zone 30 of commercial reactors can beany volume, for example, ranging from 500 ft³ or smaller to 3,000 ft³(as shown in Table 1) or larger. Reaction zone flow rates can be of anyvalue, for example, ranging from 65,000 kg/hr or less to 500,000 kg/hr(as shown in Table 1) or more. The concentration of carbon monoxide,[CO], can be in the ranges disclosed herein, for example, ranging fromabout 0.0001 mol % to about 0.15 mol %; alternatively, ranging fromabout 0.001 mol % to about 0.15 mol % (as shown in Table 1) or less.

It is understood the disclosed embodiments can comprise various othervalue combinations of volume (V), flow rate (F), and carbon monoxideconcentrations [CO] which, when combined provide a flow index (I_(F)) inthe ranges disclosed herein.

After hydrogenation in the reaction zone 30, the produced unsaturatedhydrocarbon can be further processed; for example, in a fractionationzone 40 (designated with a dashed line) which is downstream of thereaction zone 30 and which can receive the second effluent stream 36from the second reaction zone 35. The fractionation zone 40 (for examplea downstream fractionation zone) can separate the second effluent stream36 into a saturated hydrocarbon stream 42 (designated with a dashedline) and an unsaturated hydrocarbon stream 44 (also designated with adashed line). In such embodiments, the fractionation zone 40 can split(in other words separate) an unsaturated hydrocarbon (for exampleethylene, propylene) from a saturated hydrocarbon (for example ethane,propane) which is received from the second reaction zone 35 via secondeffluent stream 36. Unsaturated hydrocarbon (for example ethylene,propylene) in stream 44 can be used in a polymerization process for theproduction of one or more polymer products. In embodiments of system 100in a frontend deethanizer configuration, the downstream fractionationzone 40 can operate at conditions (for example temperatures andpressures) which separate components of the second effluent stream 36such that an unsaturated hydrocarbon can be separated from a saturatedhydrocarbon. The downstream fractionation zone 40 can comprise a vesselin which a suitable technique can be used to separate the unsaturatedhydrocarbon and saturated hydrocarbon.

In embodiments, the system 100 can additionally comprise any equipmentassociated with hydrogenation processes, such as but not limited to, oneor more pumps, one or more control devices, one or more measurementinstruments (for example thermocouples, transducers, analyzers, and flowmeters), one or more alternative inlet lines, one or more outlet lines,one or more valves, one or more reboilers, one or more condensers, oneor more accumulators, one or more tanks, one or more filters, one ormore compressors, one or more dryers, or combinations thereof.

In embodiments, the hydrocarbon stream 24 can comprise a highlyunsaturated hydrocarbon, an unsaturated hydrocarbon, a saturatedhydrocarbon, hydrogen, carbon monoxide, to or combinations thereof.

In embodiments, a hydrogen stream 32 can feed to the reaction zone 30.In reaction zone 30 embodiments having multiple stages, hydrogen canfeed to the first stage 31 of the reaction zone 30, to the second stage35 of the reaction zone 30, or both. In embodiments having hydrogenstream 32, the hydrocarbon stream 24 and hydrogen stream 32 can becombined in a single stream that is fed to the reaction zone 30 (forexample to the first stage 31 in embodiments having multiple stages).

In embodiments, carbon monoxide can be contained in the feed to thereaction zone 30 (for example the first stage 31, second stage 35, orboth in embodiments having multiple stages) via a separate stream. Inembodiments, carbon monoxide can feed to the reaction zone 30 (forexample the first stage 31, second stage 35, or both in embodimentshaving multiple stages) by combining a separate stream comprising carbonmonoxide with a stream such as hydrocarbon stream 24, hydrogen stream32, or both. In embodiments, carbon monoxide can feed to the reactionzone 30 (for example the first stage 31, second stage 35, or both inembodiments having multiple stages) via both a separate streamcomprising carbon monoxide; and a separate stream comprising carbonmonoxide combined with a stream such as hydrocarbon stream 24, hydrogenstream 32, or both. In an embodiment, the amount of carbon monoxide inthe reaction zone 30 can range from about 0.0001 mol % to about 0.15 mol% based on the total moles of fluid in the reaction zone 30.

The reactive and inert components within the first stage 31, or secondstage 35, or both stages of the reaction zone 30 can collectively bereferred to as a reaction medium. The amount (for example moles, weight,mass, flow, concentration, described in units of mol %, wt. %, moleratio, or other means for determining concentration, other indicator ofamount, or combinations thereof) of the components of the reactionmedium within the first stage 31 and second stage 35 can change overtime and can depend on the location of the reaction medium within thefirst stage 31, the second stage 35, or both stages. Generally, ashydrogenation occurs in the first stage 31, the amount of a highlyunsaturated hydrocarbon in the reaction medium decreases in the firststage 31. After the reaction medium leaves the first stage 31, theamount of the highly unsaturated hydrocarbon in the reaction mediumfurther decreases as hydrogenation occurs in the second stage 35.Conversely, as hydrogenation occurs in the first stage 31, the amount ofthe yielded product comprising the unsaturated hydrocarbon (andoptionally saturated hydrocarbon) in the reaction medium increases inthe first stage 31. After the reaction medium exits the first stage 31in the first effluent stream 33 and flows to the second stage 35, theamount of yielded product comprising the unsaturated hydrocarbon (andoptionally a saturated hydrocarbon) in the reaction medium furtherincreases as hydrogenation occurs in the second stage 35.

In embodiments, the reaction medium, depending on its location withinthe system 100 can comprise an unsaturated hydrocarbon, a highlyunsaturated hydrocarbon, a saturated hydrocarbon, hydrogen, carbonmonoxide, or combinations thereof.

For example, within the first stage 31, the reaction medium can comprisean unsaturated hydrocarbon which is the product of the hydrogenation ofthe highly unsaturated hydrocarbon in the first stage 31, theunsaturated hydrocarbon which was originally contained in thehydrocarbon stream 24 and are not the product of hydrogenation in thefirst stage 31, those highly unsaturated hydrocarbon which wasoriginally contained in the hydrocarbon stream 24 and are unreacted orunconverted in the first stage 31, the saturated hydrocarbon which is aside product of the hydrogenation reaction in the first stage 31, thesaturated hydrocarbon which was originally contained in the hydrocarbonstream 24, hydrogen fed to the first stage 31 via stream 32 (for examplein a backend configuration), hydrogen which was originally contained inthe hydrocarbon stream 24 (for example in a frontend deethanizer orfrontend depropanizer configuration), carbon monoxide originallycontained in the hydrocarbon stream 24 (for example in a frontenddeethanizer or frontend depropanizer configuration), carbon monoxide fedto the first stage 31 (for example in a backend configuration), orcombinations thereof.

The first effluent stream 33 flows from the first stage 31 to the secondstage 35 and can comprise a unsaturated hydrocarbon which is the productof the hydrogenation of a highly unsaturated hydrocarbon in the firststage 31, the unsaturated hydrocarbon which was originally contained inthe hydrocarbon stream 24 and is not the product of hydrogenation in thefirst stage 31, second stage 35, or both stages, a highly unsaturatedhydrocarbon which was originally contained in the hydrocarbon stream 24and are unreacted or unconverted in the first stage 31, a saturatedhydrocarbon which is a side product of the hydrogenation reaction in thefirst stage 31, the saturated hydrocarbon which was originally containedin the hydrocarbon stream 24, hydrogen fed to the first stage 31 viastream 32 (for example in a backend configuration), hydrogen which wasoriginally contained in the hydrocarbon stream 24 (for example in afrontend deethanizer or frontend depropanizer configuration), carbonmonoxide originally contained in the hydrocarbon stream 24 (for examplein a frontend deethanizer or frontend depropanizer configuration),carbon monoxide fed to the first stage 31 (for example in a backendconfiguration), or combinations thereof.

Within the second stage 35, the reaction medium can comprise anunsaturated hydrocarbon which is the product of the hydrogenation of thehighly unsaturated hydrocarbon in the first stage 31, an unsaturatedhydrocarbon which is the product of the hydrogenation of the highlyunsaturated hydrocarbon in the second stage 35, the unsaturatedhydrocarbon which was originally contained in the hydrocarbon stream 24and are not the product of hydrogenation in the first stage 31, secondstage 35, or both stages, a highly unsaturated hydrocarbon which wasoriginally contained in the hydrocarbon stream 24 and are unreacted orunconverted in the second stage 35, a saturated hydrocarbon which is aside product of the hydrogenation reaction in the first stage 31, secondstage 35, or both stages, the saturated hydrocarbon which was originallycontained in the hydrocarbon stream 24, hydrogen fed to the first stage31 via stream 32 (and passed to the second stage 35) (for example in abackend configuration), hydrogen which was originally contained in thehydrocarbon stream 24 (for example in a frontend deethanizer or frontenddepropanizer configuration), carbon monoxide originally contained in thehydrocarbon stream 24 (for example in a frontend deethanizer or frontenddepropanizer configuration), carbon monoxide fed to the first stage 31,carbon monoxide fed to the second stage 35 (for example in a backendconfiguration), or combinations thereof.

The second effluent stream 36 can comprise an unsaturated hydrocarbonwhich is the product of the hydrogenation of the highly unsaturatedhydrocarbon in the first stage 31, an unsaturated hydrocarbon which isthe product of the hydrogenation of the highly unsaturated hydrocarbonin the second stage 35, the unsaturated hydrocarbon which was originallycontained in the hydrocarbon stream 24 and are not the product ofhydrogenation in stages 31, stage 35, or both stages, a highlyunsaturated hydrocarbon which was originally contained in thehydrocarbon stream 24 and are unreacted or unconverted in the secondstage 35, a saturated hydrocarbon which is side product of thehydrogenation reaction in the first stage 31, second stage 35, or bothstages, the saturated hydrocarbon which was originally contained in thehydrocarbon stream 24, hydrogen fed to the first stage 31 via stream 32(and passed to the second stage 35), hydrogen which was originallycontained in the hydrocarbon stream 24, carbon monoxide originallycontained in the hydrocarbon stream 24, carbon monoxide fed to thereaction zone 30 (for example, to the first stage 31, the second stage35), or combinations thereof.

In embodiments where the highly unsaturated hydrocarbon fed to thereaction zone 30 (for example first stage 31 or first reactor ofreaction zone 30) can comprise acetylene, the mole ratio of hydrogen tothe acetylene being fed to the reaction zone 30 (for example first stage31 or first reactor of reaction zone 30) can be in the range of fromabout 10:1 to about 3000:1; alternatively, from about 10:1 to about2000:1; alternatively, from about 10:1 to about 1500:1; alternatively,from about 0.1:1 to about 100:1; alternatively, from about 0.1:1 toabout 10:1.

In embodiments, the reaction zone 30 can comprise at least onehydrogenation catalyst. The at least one hydrogenation catalyst cancomprise an embodiment of the hydrogenation catalyst disclosed herein ormultiple embodiments of the hydrogenation catalyst disclosed herein.

In embodiments where reaction zone 30 is one of two or more (in otherwords multiple) reaction zones, reaction zone 30 can comprise anembodiment of the hydrogenation catalyst and another reaction zone cancomprise the same or different embodiment of the hydrogenation catalyst,or a different hydrogenation catalyst known in the art with the aid ofthis disclosure. In embodiments where a reaction zone (for examplereaction zone 30) has multiple stages (for example the first stage 31 ofthe reaction zone 30 and second stage 35 of the reaction zone 30), oneof the stages (for example the first stage 31) can comprise anembodiment of the hydrogenation catalyst disclosed herein or multipleembodiments of the hydrogenation catalyst disclosed herein, and anotherof the stages (for example the second stage 35) can comprise the same ordifferent embodiment of the hydrogenation catalyst, or a differenthydrogenation catalyst known in the art with the aid of this disclosure.

FIG. 2 illustrates embodiments of the system 200 and process can includea raw gas configuration. In system 200, the reaction zone 30 cancomprise one or more hydrogenation reactors (for example first stage 31and second stage 35) that belong to an acetylene removal unit (ARU) ofan unsaturated hydrocarbon production plant in a raw gas configuration.In a raw gas configuration, the cracked gas stream 14 can feed to thefirst stage 31, the second stage 35, or both, without first passingthrough a fractionation zone. In such raw gas configurations, thecracked gas stream 14 comprising hydrogen, carbon monoxide, propane,ethane, methane, methylacetylene, propadiene, acetylene, ethylene,propylene, C₄ ⁺ components (C₄ ⁺ components comprise C₄ hydrocarbons andheavier), or combinations thereof, can feed directly to the first stage31, the second stage 35, or both. In the raw gas configuration, a highlyunsaturated hydrocarbon (e.g., acetylene, methylacetylene, propadienes,butadienes, pentadienes, or combinations thereof) fed to the reactionzone 30 is hydrogenated in the first stage 31, second stage 35, or both,as described above. Components of the effluent stream 36 flowing fromthe reaction zone 30 may be further processed and/or separated. Forexample, the components in stream 36 may be separated according totechniques similar to those described above for fractionation zone 20,fraction zone 40, or both.

Embodiments of the hydrogenation catalyst described herein can generallybe used for hydrogenating a highly unsaturated hydrocarbon to yield aproduct comprising an unsaturated hydrocarbon. For example, thehydrogenation catalyst can be contacted with at least a portion of thehighly unsaturated hydrocarbon in the presence of hydrogen in a singlestage reaction zone or in at least one of the first stage 31 of thereaction zone 30 and the second stage 35 of the reaction zone 30.

In embodiments, the hydrogenation catalyst can comprise any compositionused for the selective hydrogenation of a highly unsaturated hydrocarbonto an unsaturated hydrocarbon which has a selectivity for conversion ofthe highly unsaturated hydrocarbon to an unsaturated hydrocarbon (forexample ethylene) of about 90 mol %, 91 mol %, 92 mol %, 93 mol %, 94mol %, 95 mol %, 96 mol %, 97 mol %, 98 mol %, 99 mol % or greater.Herein “selectivity” or “hydrogenation selectivity” generally refers tothe amount of the highly unsaturated hydrocarbon (for example acetylene)which is converted to an unsaturated hydrocarbon (for example ethylene).For example, at a total conversion of 99 mol %, 99 moles of the highlyunsaturated hydrocarbon convert to a product made of compounds such asthe unsaturated hydrocarbon and saturated hydrocarbon, while one mole ofthe highly unsaturated hydrocarbon is unconverted or unreacted. Aselectivity of 90.9 mol % to the unsaturated hydrocarbon when totalconversion is at 99 mol % can indicate that, of the 99 moles of thehighly unsaturated hydrocarbon which were converted to the product, 90moles of the highly unsaturated hydrocarbon were converted to theunsaturated hydrocarbon while 9 moles of the highly unsaturatedhydrocarbon were converted to other compounds such as a saturatedhydrocarbon or other side products of the hydrogenation reaction.

In embodiments, the selectivity can be defined as:

$S = {100 \times \left( \frac{{{UH}(p)} - {{UH}(f)}}{{{HUH}(f)} - {{HUH}(p)}} \right)}$

where S is selectivity in mol %, UH(p) is moles of the unsaturatedhydrocarbon in the product, UH(f) is moles of the unsaturatedhydrocarbon in the hydrocarbon stream 24, HUH(f) is the moles of highlyunsaturated hydrocarbon in the hydrocarbon stream 24, and HUH(p) is themoles of the highly unsaturated hydrocarbon in the product.

In embodiments, the selectivity of the hydrogenation catalyst in thereaction zone 30 to an unsaturated hydrocarbon can vary. For example,the selectivity of the hydrogenation catalyst for conversion of thehighly unsaturated hydrocarbon to the unsaturated hydrocarbon in thefirst stage 31 of the reaction zone 30 can be about 90 mol %, 91 mol %,92 mol %, 93 mol %, 94 mol %, 95 mol %, 96 mol %, 97 mol %, 98 mol %, 99mol % or greater, while the selectivity of the hydrogenation catalystfor conversion of the highly unsaturated hydrocarbon to the unsaturatedhydrocarbon in the entire reaction zone 30 can be about 70 mol %, 75 mol%, 80 mol %, 85 mol %, 90 mol %, 91 mol %, 92 mol %, 93 mol %, 94 mol %,95 mol %, 96 mol %, 97 mol %, 98 mol %, 99 mol % or greater.

In embodiments, the hydrogenation catalyst can comprise an inorganicsupport and palladium. In additional embodiments, the hydrogenationcatalyst can further comprise an organophosphorus compound (for exampleimpregnated in or on the inorganic support thereof).

In an embodiment, the inorganic support can comprise aluminas, silicas,titanias, zirconias, aluminosilicates (for example clays, ceramics,zeolites, or combinations thereof), spinels (for example zinc aluminate,zinc titanate, magnesium aluminate, or combinations thereof), orcombinations thereof. In an embodiment, the support can comprise analumina support. In some embodiments, the alumina support can comprisean alpha (α)-alumina support or a chlorided alpha alumina support.

The inorganic support can have a surface area of from about 2 to about100 square meters per gram (m²/g); alternatively, from about 2 m²/g toabout 75 m²/g; alternatively, from about 3 m²/g to about 50 m²/g;alternatively, from about 4 m²/g to about 25 m²/g; alternatively, fromabout 5 m²/g to about 15 m²/g; alternatively, from about 5 m²/g to about10 m²/g. The surface area of the support can be determined using anysuitable method. An example of a suitable method includes the Brunauer,Emmett, and Teller (“BET”) method, which measures the quantity ofnitrogen adsorbed on the support. Alternatively, the surface area of thesupport can be measured by a mercury intrusion method such as isdescribed in ASTM UOP 578-02, entitled “Automated Pore Volume and PoreSize Distribution of Porous Substances by MERCURY Porosimetry,” which isincorporated herein by reference in its entirety.

Particles of the inorganic support generally have an average diameter offrom about 1 mm to about 10 mm; alternatively, from about 1 mm to about6 mm; alternatively, from about 2 mm to about 6 mm; alternatively, fromabout 3 mm to about 5 mm 9 the last batch of spheres from Sasol were 2.5to 4 mm in diameter). The inorganic support can have any suitable shape,including round or spherical (for example spheres, ellipsoidal, orcombinations thereof), pellets, cylinders, granules (for exampleregular, irregular, or combinations thereof), extrudates (trilobe,quadrilobe, rings, wagonwheel, monoliths, or combinations thereof).Methods for shaping particles include, for example, extrusion, spraydrying, pelletizing, marumerizing, agglomeration, oil drop, and thelike. In an embodiment, the shape of the inorganic support can becylindrical. In an alternative embodiment, the shape of the inorganicsupport can be spherical. In an alternative embodiment, the shape of theinorganic support can be an extrudate.

In an embodiment, the inorganic support can be present in an amount suchthat it can comprise the balance of the hydrogenation catalyst when allother components are accounted for.

In an embodiment, the hydrogenation catalyst can comprise palladium. Thepalladium can be added to the inorganic support by contacting theinorganic support with a palladium-containing compound to form apalladium supported catalyst as will be described in more detail laterherein. Examples of suitable palladium-containing compounds includewithout limitation palladium chloride, palladium nitrate, ammoniumhexachloropalladate, ammonium tetrachloropalladate, palladium acetate,palladium bromide, palladium iodide, tetraamminepalladium nitrate, orcombinations thereof. In an embodiment, the palladium-containingcompound is a component of an aqueous solution. In an embodiment, thepalladium-containing compound can be a component of an acidic solution,for example an aqueous solution comprising a mineral acid. An example ofpalladium-containing solution suitable for use in this disclosureincludes without limitation a solution comprising palladium metal.

In an embodiment, the hydrogenation catalyst can be prepared using apalladium-containing compound in an amount of from about 0.005 wt. % toabout 5 wt. % based on the total weight of the hydrogenation catalyst;alternatively, from about 0.01 wt. % to about 3 wt. %; alternatively,from about 0.02 wt. % to about 1 wt. %; alternatively, from about 0.02wt. % to about 0.5 wt. %; alternatively, from about 0.02 wt. % to about0.1 wt. %; alternatively, from about 0.02 wt. % to about 0.04 wt. %. Theamount of palladium incorporated into the hydrogenation catalyst can bein the range described herein for the amount of palladium-containingcompound used to prepare the hydrogenation catalyst.

In an embodiment, the hydrogenation catalyst can further comprise anorganophosphorus compound. In an embodiment, the organophosphoruscompound can be represented by the general formula of(R)_(x)(OR′)_(y)P═O; wherein x and y are integers ranging from 0 to 3and x plus y equals 3; wherein each R can be hydrogen, a hydrocarbylgroup, or combinations thereof; and wherein each R′ can be a hydrocarbylgroup. In some embodiments, the organophosphorus compound can includecompounds such as phosphine oxides, phosphinates, phosphonates,phosphates, or combinations of any of the foregoing. For purposes ofthis application, the term “hydrocarbyl(s)” or “hydrocarbyl group(s)” isused herein in accordance with the definition specified by IUPAC: as aunivalent group or groups derived by the removal of one hydrogen atomfrom a carbon atom of a “hydrocarbon.” A hydrocarbyl group can be analiphatic hydrocarbon, inclusive of acyclic and cyclic groups. Ahydrocarbyl group can include rings, ring systems, aromatic rings, andaromatic ring systems. Hydrocarbyl groups can include, by way ofexample, aryl, alkyl, cycloalkyl, and combinations of these groups,among others. Hydrocarbyl groups can be linear or branched unlessotherwise specified. For the purposes of this application, the terms“alkyl,” or “cycloalkyl” refers to a univalent group derived by removalof a hydrogen atom from any carbon atom of an alkane. For the purposesof this application, the terms “aryl,” or “arylene” refers to aunivalent group derived by removal of a hydrogen atom from any carbonatom of an aryl ring.

In an embodiment, the hydrocarbyl group can have from 1 to 30 carbonatoms; alternatively, from 2 to 20 carbon atoms; alternatively, from 3to 15 carbon atoms. In other embodiments, the hydrocarbyl group can havefrom about 6 to about 30 carbon atoms; alternatively, from about 6 toabout 20 carbon atoms; alternatively, from about 6 to about 15 carbonatoms.

Generally, the alkyl group for any feature which calls for an alkylgroup described herein can be a methyl, ethyl, n-propyl (1-propyl),isopropyl (2-propyl), n-butyl (1-butyl), sec-butyl (2-butyl), isobutyl(2-methyl-1-propyl), tent-butyl (2-methyl-2-propyl), n-pentyl(1-pentyl), 2-pentyl, 3-pentyl, 2-methyl-1-butyl, tent-pentyl(2-methyl-2-butyl), 3-methyl-1-butyl, 3-methyl-2-butyl, neo-pentyl(2,2-dimethyl-1-propyl), n-hexyl (1-hexyl) group. Persons havingordinary skill in the art with the aids of this disclosure will readilyrecognize which alkyl group represents primary, secondary, or tertiaryalkyl groups.

Organophosphorus compounds described herein are not considered toencompass elemental phosphorus, or inorganic phosphorus compounds,except that which can be produced during the preparation of thehydrogenation catalyst described herein. Inorganic phosphorus compoundsencompass monobasic, dibasic, and tribasic phosphates such as tribasicpotassium phosphate (K₃PO₄), tribasic sodium phosphate (Na₃PO₄), dibasicpotassium phosphate (K₂HPO₄), dibasic sodium phosphate (Na₂HPO₄),monobasic potassium phosphate (KH₂PO₄), and monobasic sodium phosphate(NaH₂PO₄). Inorganic phosphorus compounds can also encompass thecorresponding phosphorus acid of above mentioned salts. Inorganicphosphorus compounds can also encompass anionic inorganic phosphoruscompounds containing pentavalent phosphorus, and halogens. Examples ofanionic inorganic phosphorus compounds include sodium and potassiumhexafluorophosphate.

An organophosphorus compound suitable for use in this disclosure can befurther characterized by a low boiling point wherein a low boiling pointrefers to a boiling point of about 100° C. Alternatively, anorganophosphorus compound suitable for use in this disclosure can befurther characterized by a high boiling point wherein a high boilingpoint refers to a boiling point of equal to or greater than about 100°C.

In an embodiment, the organophosphorus compound can comprise a phosphineoxide which can be represented by the general formula of (R)₃P═O;wherein each R can be hydrogen, a hydrocarbyl group, or combinationsthereof. Examples of phosphine oxides suitable for use in thisdisclosure include without limitation butyldiethylphosphine oxide,butyldimethylphosphine oxide, butyldiphenylphosphine oxide,butyldipropylphosphine oxide, decyldiethylphosphine oxide,decyldimethylphosphine oxide, decyldiphenylphosphine oxide,dibutyl(2-methylphenyl)-phosphine oxide,diethyl(3-methylphenyl)-phosphine oxide, ethyldioctylphosphine oxide,ethyldibutylphosphine oxide, ethyldimethylphosphine oxide,ethyldiphenylphosphine oxide, ethyldipropylphosphine oxide,heptyldibutylphosphine oxide, heptyldiethylphosphine oxide,heptyldimethyl phosphine oxide, heptyldipentylphosphine oxide,heptyldiphenylphosphine oxide, hexyldibutylphosphine oxide,hexyldiethylphosphine oxide, hexyldimethyl phosphine oxide,hexyldipentylphosphine oxide, hexyldiphenylphosphine oxide,methylbis(4-methylphenyl)-phosphine oxide, methyldibutylphosphine oxide,methyldidecylphosphine oxide, methyldiethylphosphine oxide,methyldiphenylphosphine oxide, methyldipropylphosphine oxide,octyldimethylphosphine oxide, octyldiphenylphosphine oxide,pentyldibutylphosphine oxide, pentyldiethylphosphine oxide,pentyldimethylphosphine oxide, pentyldiphenylphosphine oxide,phenyldibutylphosphine oxide, phenyldiethylphosphine oxide,phenyldimethylphosphine oxide, phenyldipropylphosphine oxide,propyldibutylphosphine oxide, propyldimethylphosphine oxide,propyldiphenylphosphine oxide, tris(2,6-dimethylphenyl)-phosphine oxide,tris(2-methylphenyl)-phosphine oxide, tris(4-methylphenyl)-phosphineoxide, tris[4-(1,1-dimethylethyl)phenyl]-phosphine oxide,(1-methylethyl)diphenyl-phosphine oxide,4-(diphenylmethyl)phenyl]diphenyl-phosphine oxide,bis(2-methylphenyl)(2-methylpropyl)-phosphine oxide, or combinationsthereof. In some embodiments, the phosphine oxides suitable for use inthis disclosure include without limitation tributylphosphine oxide,triethylphosphine oxide, triheptylphosphine oxide, trimethylphosphineoxide, trioctylphosphine oxide, tripentylphosphine oxide,tripropylphosphine oxide, triphenylphosphine oxide, or combinationsthereof.

In an embodiment, the organophosphorus compound can comprise an organicphosphate which can be represented by the general formula of (OR′)₃P═O;wherein each R′ can be a hydrocarbyl group. Examples of phosphatessuitable for use in this disclosure include without limitation(1-methylethyl)diphenyl phosphate, 2-ethylphenyldiphenyl phosphate,4-(diphenylmethyl)phenyl]diphenyl phosphate,bis(2-methylphenyl)(2-methylpropyl) phosphate, butyldiethylphosphate,butyldimethylphosphate, butyldiphenylphosphate, butyldipropylphosphate,crecyldiphenylphosphate, decyldiethylphosphate, decyldimethylphosphate,decyldiphenylphosphate, dibutyl(2-methylphenyl) phosphate,diethyl(3-methylphenyl) phosphate, ethyldibutylphosphate,ethyldimethylphosphate, ethyldioctylphosphate, ethyldiphenylphosphate,ethyl dipropylphosphate, heptyldibutylphosphate, heptyldiethylphosphate,heptyldimethyl phosphate, heptyldipentylphosphate,heptyldiphenylphosphate, hexyldibutylphosphate, hexyldiethylphosphate,hexyldimethyl phosphate, hexyldipentylphosphate, hexyldiphenylphosphate,methylbis(4-methylphenyl) phosphate, methyldibutylphosphate,methyldidecylphosphate, methyldiethylphosphate, methyldiphenylphosphate,methyldipropylphosphate, octyldimethylphosphate, octyldiphenylphosphate,pentyldibutylphosphate, pentyldiethylphosphate, pentyldimethylphosphate,pentyldiphenylphosphate, phenyldibutylphosphate, phenyldiethylphosphate, phenyldimethylphosphate, phenyldipropylphosphate,propyldibutylphosphate, propyldimethylphosphate,propyldiphenylphosphate, tri(2,3-dichloropropyl) phosphate,tri(2,6-dimethylphenyl) phosphate, tri(2-chloroethyl) phosphate,tri(nonylphenyl) phosphate, tris(2,6-dimethylphenyl) phosphate,tris(2-methylphenyl) phosphate, tris(4-methylphenyl) phosphate,tris[4-(1,1-dimethylethyl)phenyl] phosphate, or combinations thereof. Insome embodiments, the phosphates suitable for use in this disclosureinclude without limitation tributylphosphate, tricresyl phosphate,tricyclohexyl phosphate, tridecylphosphate, triethylphosphate,triheptylphosphate, triisopropyl phosphate, trimethylphosphate,trioctadecyl phosphate, trioctylphosphate, tripentylphosphate,triphenylphosphate, tripropylphosphate, trixylylphosphate, orcombinations thereof.

In an embodiment, the organophosphorus compound can comprise aphosphinate, which can be represented by the general formula of(R)₂(OR′)P═O; wherein each R can be hydrogen, a hydrocarbyl group, orcombinations thereof; and wherein each R′ can be a hydrocarbyl group.Examples of phosphinates suitable for use in this disclosure includewithout limitation butyl butylphosphinate, butyl dibutylphosphinate,butyl diethylphosphinate, butyl diphenylphosphinate, butyldipropylphosphinate, butyl ethylphosphinate, butyl heptylphosphinate,butyl hexylphosphinate, butyl pentylphosphinate, butylphenylphosphinate, butyl propylphosphinate, decyl pentylphosphinate,butyl butylpentylphosphinate, ethyl butylphosphinate, ethyldecylphosphinate, ethyl dibutylphosphinate, ethyl diethylphosphinate,ethyl dimethylphosphinate, ethyl diphenylphosphinate, ethyldipropylphosphinate, ethyl ethylphosphinate, ethyl heptylphosphinate,ethyl hexylphosphinate, ethyl octylphosphinate, ethyl pentylphosphinate,ethyl phenylphosphinate, ethyl propylphosphinate, heptyldibutylphosphinates, heptyl pentylphosphinate, heptylphosphinate, hexyldibutylphosphinate, hexyl pentylphosphinate, isopropyldiphenylphosphinate, methyl butylphosphinate, methyl decylphosphinate,methyl dibutylphosphinate, methyl diethylphosphinate, methyldimethylphosphinate, methyl diphenylphosphinates, methyldipropylphosphinate, methyl ethylphosphinate, methyl heptylphosphinate,methyl hexylphosphinate, methyl octylphosphinate, methylpentylphosphinate, methyl phenylphosphinate, methyl propylphosphinate,octyl pentylphosphinate, octylphosphinate, pentyl dibutylphosphinate,pentylphosphinate, phenyl butylphosphinate, phenyl decylphosphinate,phenyl dibutylphosphinate, phenyl diethylphosphinate, phenyldiethylphosphinate, phenyl dimethylphosphinate, phenyldiphenylphosphinate, phenyl diphenylphosphinate, phenyldipropylphosphinate, phenyl ethylphosphinate, phenyl heptylphosphinate,phenyl hexylphosphinate, phenyl octylphosphinate, phenylpentylphosphinate, phenyl pentylphosphinate, phenyl phenylphosphinate,phenyl propylphosphinate, phenylphosphinate, propyl diphenylphosphinate,or combinations thereof.

In an embodiment, the organophosphorus compound can comprise aphosphonate, which can be represented by the general formula of(R)(OR′)₂P═O; wherein each R can be hydrogen, a hydrocarbyl group, orcombinations thereof; and wherein each R′ can be a hydrocarbyl group.Examples of phosphonates suitable for use in this disclosure includewithout limitation (1-methylethyl)diphenyl phosphonate,2-ethylphenyldiphenyl phosphonate, 4-(diphenylmethyl)phenyl]diphenylphosphonate, bis(2-methylphenyl)(2-methylpropyl) phosphonate,butyldiethylphosphonate, butyldimethylphosphonate,butyldiphenylphosphonate, butyldipropylphosphonate,crecyldiphenylphosphonate, decyldiethylphosphonate,decyldimethylphosphonate, decyldiphenylphosphonate,dibutyl(2-methylphenyl) phosphonate, diethyl(3-methylphenyl)phosphonate, ethyldibutylphosphonate, ethyldimethylphosphonate,ethyldioctylphosphonate, ethyldiphenylphosphonate,ethyldipropylphosphonate, heptyldibutylphosphonate,heptyldiethylphosphonate, heptyldimethylphosphonate,heptyldipentylphosphonate, heptyldiphenylphosphonate,hexyldibutylphosphonate, hexyldiethylphosphonate,hexyldimethylphosphonate, hexyldipentylphosphonate,hexyldiphenylphosphonate, methylbis(4-methylphenyl) phosphonate,methyldibutylphosphonate, methyldidecylphosphonate,methyldiethylphosphonate, methyldiphenylphosphonate,methyldipropylphosphonate, octyldimethylphosphonate,octyldiphenylphosphonate, pentyldibutylphosphonate,pentyldiethylphosphonate, pentyldimethylphosphonate,pentyldiphenylphosphonate, phenyldibutylphosphonate,phenyldiethylphosphonate, phenyldimethylphosphonate,phenyldipropylphosphonate, propyldibutylphosphonate,propyldimethylphosphonate, propyldiphenylphosphonate,tri(2,3-dichloropropyl) phosphonate, tri(2,6-dimethylphenyl)phosphonate, tri(2-chloroethyl) phosphonate, tri(nonylphenyl)phosphonate, tris(2,6-dimethylphenyl) phosphonate, tris(2-methylphenyl)phosphonate, tris(4-methylphenyl) phosphonate,tris[4-(1,1-dimethylethyl)phenyl] phosphonate, or combinations thereof.In some embodiments, the phosphonates suitable for use in thisdisclosure include without limitation tributylphosphonate, tricresylphosphonate, tricyclohexyl phosphonate, tridecylphosphonate,triethylphosphonate, triheptylphosphonate, triisopropyl phosphonate,trimethylphosphonate, trioctadecyl phosphonate, trioctylphosphonate,tripentylphosphonate, triphenylphosphonate, tripropylphosphonate,trixylylphosphonate, or combinations thereof.

In an embodiment, the hydrogenation catalyst can comprise a precursor tothe organophosphorus compound. The organophosphorus compound precursorcan comprise any material which can be converted to the organophosphoruscompound which activates the hydrogenation catalyst under the conditionsto which the hydrogenation catalyst is exposed and that is compatiblewith the other components of the hydrogenation catalyst. In anembodiment, the organophosphorus compound precursor can be representedby the general formula of (R)_(x)(OR′)_(y)P; wherein x and y areintegers ranging from 0 to 3 and x plus y equals 3; wherein each R canbe hydrogen, a hydrocarbyl group, or combinations thereof; and whereineach R′ can be a hydrocarbyl group. The organophosphorus compoundprecursor can include without limitation phosphines, phosphites,phosphinites, phosphonites, or combinations thereof. In an embodiment,the organophosphorus compound precursor can comprise a phosphine thatcan form a phosphine oxide when exposed to an oxidizing agent,temperatures greater than about 20° C., or combinations thereof. In anembodiment, the organophosphorus compound precursor can comprise aphosphite that can form a phosphate when exposed to an oxidizing agent,temperatures greater than about 20° C., or combinations thereof. In anembodiment, the organophosphorus compound precursor can comprise aphosphinite that can form a phosphinate when exposed to oxidizing agent,temperatures greater than about 20° C., or combinations thereof. In anembodiment, the organophosphorus compound precursor can comprise aphosphonite that can form a phosphonate when exposed to air,temperatures greater than about 20° C., or combinations thereof.

In an embodiment, the organophosphorus compound can comprise phosphines,which can be represented by the general formula of (R)₃P; wherein each Rcan be hydrogen, a hydrocarbyl group, or combinations thereof. Examplesof phosphines suitable for use as phosphine oxide precursors in thisdisclosure include without limitation (1-methylethyl)diphenylphosphine,2-ethylphenyldiphenyl phosphine,4-(diphenylmethyl)phenyl]diphenylphosphine,bis(2-methylphenyl)(2-methylpropyl) phosphine, butyldiethylphosphine,butyldimethylphosphine, butyldiphenylphosphine, butyldipropylphosphine,crecyldiphenylphosphine, cyclohexyldiphenylphosphine,decyldiethylphosphine, decyldimethylphosphine, decyldiphenylphosphine,dibutyl(2-methylphenyl) phosphine, dicyclohexylphenylphosphine,diethyl(3-methylphenyl)phosphine, ethyldibutylphosphine, ethyl dimethylphosphine, ethyldioctylphosphine, ethyldiphenylphosphine,ethyldipropylphosphine, heptyldibutylphosphine, heptyldiethylphosphine,heptyldimethyl phosphine, heptyldipentylphosphine,heptyldiphenylphosphine, hexyldibutylphosphine, hexyldiethylphosphine,hexyldimethyl phosphine, hexyldipentylphosphine, hexyldiphenylphosphine,methylbis(4-methylphenyl) phosphine, methyldibutylphosphine,methyldidecylphosphine, methyldiethylphosphine, methyldiphenylphosphine,methyldipropylphosphine, octyldimethylphosphine, octyldiphenylphosphine,pentyldibutylphosphine, pentyldiethylphosphine, pentyldimethylphosphine,pentyldiphenylphosphine, phenyldibutylphosphine, phenyldiethylphosphine,phenyldimethylphosphine, phenyldipropylphosphine,propyldibutylphosphine, propyldimethylphosphine,propyldiphenylphosphine, tri(2,3-dichloropropyl) phosphine,tri(2,6-dimethylphenyl) phosphine, tri(2-chloroethyl) phosphine,tri(nonylphenyl) phosphine, tris(2,6-dimethylphenyl) phosphine,tris(2-methylphenyl) phosphine, tris(4-methylphenyl) phosphine,tris(methoxyphenyl)phosphine, tris[4-(1,1-dimethylethyl)phenyl]phosphine, or combinations thereof. In some embodiments, the phosphinessuitable for use in this disclosure include without limitationtributylphosphine, tricresyl phosphine, tricyclohexyl phosphine,tridecylphosphine, triethylphosphine, triheptylphosphine,triisopropylphosphine, trimethylphosphine, trioctadecylphosphine,trioctylphosphine, tripentylphosphine, triphenylphosphine,tripropylphosphine, tri-t-butylphosphine, tritolylphosphine,trixylylphosphine, or combinations thereof.

In an embodiment, the organophosphorus compound can comprise phosphites,which can be represented by the general formula of (OR′)₃P; wherein eachR′ can be a hydrocarbyl group. Examples of phosphites suitable for useas phosphate precursors in this disclosure include without limitation(1-methylethyl)diphenylphosphite, 2-ethylphenyldiphenyl phosphite,4-(diphenylmethyl)phenyl]diphenylphosphite,bis(2-methylphenyl)(2-methylpropyl) phosphite, butyldiethylphosphite,butyldimethylphosphite, butyldiphenylphosphite, butyldipropylphosphite,crecyldiphenylphosphite, cyclohexyldiphenylphosphite,decyldiethylphosphite, decyldimethylphosphite, decyldiphenylphosphite,dibutyl(2-methylphenyl) phosphite, dicyclohexylphenylphosphite,diethyl(3-methylphenyl)phosphite, ethyldibutylphosphite,ethyldimethylphosphite, ethyldioctylphosphite, ethyldiphenylphosphite,ethyldipropylphosphite, heptyldibutylphosphite, heptyldiethylphosphite,heptyldimethyl phosphite, heptyldipentylphosphite,heptyldiphenylphosphite, hexyldibutylphosphite, hexyldiethylphosphite,hexyldimethyl phosphite, hexyldipentylphosphite, hexyldiphenylphosphite,methylbis(4-methylphenyl) phosphite, methyldibutylphosphite,methyldidecylphosphite, methyldiethylphosphite, methyldiphenylphosphite,methyldipropylphosphite, octyldimethylphosphite, octyldiphenylphosphite,pentyldibutylphosphite, pentyldiethylphosphite, pentyldimethylphosphite,pentyldiphenylphosphite, phenyldibutylphosphite, phenyldiethylphosphite,phenyldimethylphosphite, phenyldipropylphosphite,propyldibutylphosphite, propyldimethylphosphite,propyldiphenylphosphite, tri(2-chloroethyl) phosphite, tri(nonylphenyl)phosphite, tris(2,3-dichloropropyl) phosphite, tris(2,6-dimethylphenyl)phosphite, tris(2-methylphenyl) phosphite, tris(4-methylphenyl)phosphite, tris(methoxyphenyl)phosphite,tris[4-(1,1-dimethylethyl)phenyl] phosphite, tri-t-butylphosphite, orcombinations thereof. In some embodiments, the phosphites suitable foruse in this disclosure include without limitation tributylphosphite,tricresyl phosphite, tricyclohexyl phosphite, tridecylphosphite,triethylphosphite, triheptylphosphite, triisopropylphosphite,trimethylphosphite, trioctadecyl phosphite, trioctylphosphite,tripentylphosphite, triphenylphosphite, tripropylphosphite,tritolylphosphite, trixylylphosphite, or combinations thereof.

In an embodiment, the organophosphorus compound can comprisephosphinites, which can be represented by the general formula of(R)₂(OR′)₁P; wherein each R can be hydrogen, a hydrocarbyl group, orcombinations thereof; and wherein each R′ can be a hydrocarbyl group.Examples of phosphinites suitable for use as phosphate precursors inthis disclosure include without limitation(1-methylethyl)diphenylphosphinite, 2-ethylphenyldiphenyl phosphinite,4-(diphenylmethyl)phenyl diphenylphosphinite,bis(2-methylphenyl)(2-methylpropyl) phosphinite,butyldiethylphosphinite, butyldimethylphosphinite,butyldiphenylphosphinite, butyldipropylphosphinite,crecyldiphenylphosphinite, cyclohexyldiphenylphosphinite,decyldiethylphosphinite, decyldimethylphosphinite,decyldiphenylphosphinite, dibutyl(2-methylphenyl) phosphinite,dicyclohexylphenylphosphinite, diethyl(3-methylphenyl)phosphinite,ethyldibutylphosphinite, ethyldimethylphosphinite,ethyldioctylphosphinite, ethyldiphenylphosphinite,ethyldipropylphosphinite, heptyldibutylphosphinite,heptyldiethylphosphinite, heptyldimethyl phosphinite,heptyldipentylphosphinite, heptyldiphenylphosphinite,hexyldibutylphosphinite, hexyldiethylphosphinite, hexyldimethylphosphinite, hexyldipentylphosphinite, hexyldiphenylphosphinite,methylbis(4-methylphenyl) phosphinite, methyldibutylphosphinite,methyldidecylphosphinite, methyldiethylphosphinite,methyldiphenylphosphinite, methyldipropylphosphinite,octyldimethylphosphinite, octyldiphenylphosphinite,pentyldibutylphosphinite, pentyldiethylphosphinite,pentyldimethylphosphinite, pentyldiphenylphosphinite,phenyldibutylphosphinite, phenyldiethylphosphinite,phenyldimethylphosphinite, phenyldipropylphosphinite,propyldibutylphosphinite, propyldimethylphosphinite,propyldiphenylphosphinite, tri(2-chloroethyl) phosphinite,tri(nonylphenyl) phosphinite, tris(2,3-dichloropropyl) phosphinite,tris(2,6-dimethylphenyl) phosphinite, tris(2-methylphenyl) phosphinite,tris(4-methylphenyl) phosphinite, tri s(methoxyphenyl)phosphinite,tris[4-(1,1-dimethylethyl)phenyl] phosphinite, tri-t-butylphosphinite,or combinations thereof. In some embodiments, the phosphinites suitablefor use in this disclosure include without limitationtributylphosphinite, tricresyl phosphinite, tricyclohexyl phosphinite,tridecylphosphinite, triethylphosphinite, triheptylphosphinite,triisopropylphosphinite, trimethylphosphinite, trioctadecyl phosphinite,trioctylphosphinite, tripentylphosphinite, triphenylphosphinite,tripropylphosphinite, tritolylphosphinite, trixylylphosphinite, orcombinations thereof.

In an embodiment, the organophosphorus compound can comprisephosphonites, which can be represented by the general formula of(R)₁(OR′)₂P; wherein each R can be hydrogen, a hydrocarbyl group, orcombinations thereof; and wherein each R′ can be a hydrocarbyl group.Examples of phosphonites suitable for use as phosphate precursors inthis disclosure include without limitation(1-methylethyl)diphenylphosphonite, 2-ethylphenyldiphenyl phosphonite,4-(diphenylmethyl)phenyl diphenylphosphonite,bis(2-methylphenyl)(2-methylpropyl) phosphonite,butyldiethylphosphonite, butyldimethylphosphonite,butyldiphenylphosphonite, butyldipropylphosphonite,crecyldiphenylphosphonite, cyclohexyldiphenylphosphonite,decyldiethylphosphonite, decyldimethylphosphonite,decyldiphenylphosphonite, dibutyl(2-methylphenyl) phosphonite,dicyclohexylphenylphosphonite, diethyl(3-methylphenyl)phosphonite,ethyldibutylphosphonite, ethyldimethylphosphonite,ethyldioctylphosphonite, ethyldiphenylphosphonite,ethyldipropylphosphonite, heptyldibutylphosphonite,heptyldiethylphosphonite, heptyldimethyl phosphonite,heptyldipentylphosphonite, heptyldiphenylphosphonite,hexyldibutylphosphonite, hexyldiethylphosphonite, hexyldimethylphosphonite, hexyldipentylphosphonite, hexyldiphenylphosphonite,methylbis(4-methylphenyl) phosphonite, methyldibutylphosphonite,methyldidecylphosphonite, methyldiethylphosphonite,methyldiphenylphosphonite, methyldipropylphosphonite,octyldimethylphosphonite, octyldiphenylphosphonite,pentyldibutylphosphonite, pentyldiethylphosphonite,pentyldimethylphosphonite, pentyldiphenylphosphonite,phenyldibutylphosphonite, phenyldiethylphosphonite,phenyldimethylphosphonite, phenyldipropylphosphonite,propyldibutylphosphonite, propyldimethylphosphonite,propyldiphenylphosphonite, tri(2-chloroethyl) phosphonite,tri(nonylphenyl) phosphonite, tris(2,3-dichloropropyl) phosphonite,tris(2,6-dimethylphenyl) phosphonite, tris(2-methylphenyl) phosphonite,tris(4-methylphenyl) phosphonite, tris(methoxyphenyl)phosphonite,tris[4-(1,1-dimethylethyl)phenyl] phosphonite, tri-t-butylphosphonite,or combinations thereof. In some embodiments, the phosphonites suitablefor use in this disclosure include without limitationtributylphosphonite, tricresyl phosphonite, tricyclohexyl phosphonite,tridecylphosphonite, triethylphosphonite, triheptylphosphonite,triisopropylphosphonite, trimethylphosphonite, trioctadecyl phosphonite,trioctylphosphonite, trip entylphosphonite, triphenylphosphonite,tripropylphosphonite, tritolylphosphonite, trixylylphosphonite, orcombinations thereof.

In an embodiment, the organophosphorus compound, organophosphoruscompound precursor, or combinations thereof, can be present in themixture for the preparation of the hydrogenation catalyst in an amountof from about 0.005 wt. % to about 5 wt. % based on the weight ofphosphorus to the total weight of the hydrogenation catalyst;alternatively, from about 0.01 wt. % to about 1 wt. %; alternatively,from about 0.01 wt. % to about 0.5 wt. %. The amount of organophosphoruscompound or phosphorus incorporated into the hydrogenation catalyst canbe in the range described herein for the amount of organophosphoruscompound or organophosphorus precursor used to prepare the hydrogenationcatalyst. Additionally, or alternatively, the amount of hydrogenationcatalyst can have about 300 ppmw phosphorous based on the total weightof the hydrogenation catalyst.

In an embodiment, the hydrogenation catalyst can further comprise one ormore selectivity enhancers. Suitable selectivity enhancers include, butare not limited to, Group 1B metals, Group 1B metal compounds, silvercompounds, fluorine, fluoride compounds, sulfur, sulfur compounds,alkali metals, alkali metal compounds, alkaline metals, alkaline metalcompounds, iodine, iodide compounds, or combinations thereof. In anembodiment, the hydrogenation catalyst can comprise one or moreselectivity enhancers which can be present in total in the mixture forpreparation of the hydrogenation catalyst in an amount of from about0.001 to about 10 wt. % based on the total weight of the hydrogenationcatalyst; alternatively, from about 0.01 to about 5 wt. %;alternatively, from about 0.01 to about 2 wt. %. The amount ofselectivity enhancer incorporated into the hydrogenation catalyst can bein the range described herein for the amount of selectivity enhancerused to prepare the hydrogenation catalyst.

In an embodiment, the selectivity enhancer can comprise silver (Ag),silver compounds, or combinations thereof. Examples of suitable silvercompounds include without limitation silver nitrate, silver acetate,silver bromide, silver chloride, silver iodide, silver fluoride, orcombinations thereof. In an embodiment, the selectivity enhancer cancomprise silver nitrate. The hydrogenation catalyst can be preparedusing silver nitrate in an amount of from about 0.005 wt. % to about 5wt. % silver based on the total weight of the hydrogenation catalyst;alternatively, from about 0.01 wt. % to about 1 wt. % silver;alternatively, from about 0.01 wt. % to about 0.5 wt. %. The amount ofsilver incorporated into the hydrogenation catalyst can be in the rangedescribed herein for the amount of silver nitrate used to prepare thehydrogenation catalyst.

In an embodiment, the selectivity enhancer can comprise alkali metals,alkali metal compounds, or combinations thereof. Examples of suitablealkali metal compounds include without limitation elemental alkalimetals, alkali metal halides (for example alkali metal fluoride, alkalimetal chloride, alkali metal bromide, alkali metal iodide), alkali metaloxides, alkali metal carbonate, alkali metal sulfate, alkali metalphosphate, alkali metal borate, or combinations thereof. In anembodiment, the selectivity enhancer can comprise potassium fluoride(KF). In another embodiment, the hydrogenation catalyst can be preparedusing an alkali metal compound in an amount of from about 0.01 wt. % toabout 5 wt. % based on the total weight of the hydrogenation catalyst;alternatively, from about 0.05 wt. % to about 2 wt. %; alternatively,from about 0.05 wt. % to about 1 wt. %. The amount of alkali metalincorporated into the hydrogenation catalyst can be in the rangedescribed herein for the amount of alkali metal compound used to preparethe hydrogenation catalyst.

In an embodiment, a method of preparing a hydrogenation catalyst caninitiate with the contacting of an inorganic support with apalladium-containing compound to form a supported palladium composition.The contacting can be carried out using any suitable technique. Forexample, the inorganic support can be contacted with thepalladium-containing compound by incipient wetness impregnation of thesupport with a palladium-containing solution. In such embodiments, theresulting supported palladium composition can have greater than about 90wt. %; alternatively, from about 92 wt. % to about 98 wt. %;alternatively, from about 94 wt. % to about 96 wt. % of the palladiumconcentrated near the periphery of the palladium supported composition,as to form a palladium skin.

The palladium skin can be any thickness as long as such thickness canpromote the hydrogenation processes disclosed herein. Generally, thethickness of the palladium skin can be in the range of from about 1micron to about 3000 microns; alternatively, from about 5 microns toabout 2000 microns; alternatively, from about 10 microns to about 1000microns; alternatively, from about 50 microns to about 500 microns.Examples of such methods are further described in more details in U.S.Pat. Nos. 4,404,124 and 4,484,015, each of which is incorporated byreference herein in its entirety.

Any suitable method can be used for determining the concentration of thepalladium in the skin of the palladium supported composition or thethickness of the skin. For example, one method involves breaking open arepresentative sample of the palladium supported composition particlesand treating the palladium supported composition particles with a dilutealcoholic solution of N,N-dimethyl-para-nitrosoaniline. The treatingsolution reacts with the palladium to give a red color that can be usedto evaluate the distribution of the palladium. Yet another technique formeasuring the concentration of the palladium in the skin of thepalladium supported composition involves breaking open a representativesample of catalyst particles, followed by treating the particles with areducing agent such as hydrogen to change the color of the skin andthereby evaluate the distribution of the palladium. Alternatively, thepalladium skin thickness can be determined using the electron microprobemethod.

The supported palladium composition formed by contacting the inorganicsupport with the palladium-containing solution optionally can be driedat a temperature of from about 15° C. to about 150° C.; alternatively,from about 30° C. to about 140° C.; alternatively, from about 60° C. toabout 130° C.; and for a period of from about 0.1 hour to about 100hours; alternatively, from about 2 hours to about 20 hours;alternatively, from about 0.3 hour to about 10 hours. Alternatively, thepalladium supported composition can be calcined. This calcining step canbe carried out at temperatures up to about 850° C.; alternatively, offrom about 150° C. to about 750° C.; alternatively, from about 150° C.to about 700° C.; alternatively, from about 150° C. to about 680° C.;and for a period of from about 0.2 hour to about 20 hours;alternatively, from about 0.5 hour to about 20 hours; alternatively,from about 1 hour to about 10 hours.

In an embodiment, a method of preparing a hydrogenation catalyst furthercan comprise contacting the supported palladium composition with anorganophosphorus compound of the type described herein (for examplephosphine oxide, phosphate, an organophosphorus compound precursor suchas a phosphate or a phosphine). The contacting can be carried out in anysuitable manner that will yield a hydrogenation catalyst meeting theparameters described herein such as for example by incipient wetnessimpregnation. Briefly, the organophosphorus compound can comprisephosphine oxide which is dissolved in a solvent, such as for example,water, acetone, isopropanol, etc., to form a phosphine oxide containingsolution. The phosphine oxide containing solution can be added to thesupported palladium composition to form a palladium/phosphine oxidesupported composition (herein this particular embodiment of thehydrogenation catalyst is referred to as a Pd/PO composition).

In some embodiments, one or more selectivity enhancers of the typedescribed previously herein can be added to the supported palladiumcomposition prior to or following the contacting of same with anorganophosphorus compound. In an embodiment, this addition can occur bysoaking the supported palladium composition (with or without theorganophosphorus compound) in a liquid comprising one or more suitableselectivity enhancers. In another embodiment, this addition can occur byincipient wetness impregnation of the supported palladium composition(with or without an organophosphorus compound) with liquid comprisingone or more suitable selectivity enhancers to form an enhanced supportedpalladium composition.

In an embodiment, silver can be added to the supported palladiumcomposition (without an organophosphorus compound). For example, thesupported palladium composition can be placed in an aqueous silvernitrate solution of a quantity greater than that necessary to fill thepore volume of the composition. The resulting material is apalladium/silver supported composition (herein this particularembodiment of the hydrogenation catalyst is referred to as a Pd/Agcomposition). In an embodiment, the Pd/Ag composition is furthercontacted with an organophosphorus compound. The contacting can becarried out as described above to form a palladium/silver/phosphineoxide composition. In another embodiment, the Pd/Ag composition isfurther contacted with a phosphine oxide compound (herein thisparticular embodiment of the hydrogenation catalyst is referred to as aPd/Ag/PO composition).

In an embodiment, one or more alkali metals can be added to the Pd/Agcomposition (prior to or following contacting with an organophosphoruscompound) using any suitable technique such as those describedpreviously herein. In an embodiment, the selectivity enhancer cancomprise potassium fluoride, and the resulting material is apalladium/silver/alkali metal fluoride supported composition (hereinthis particular embodiment of the hydrogenation catalyst is referred toas a Pd/Ag/KF composition).

In an embodiment, the supported palladium composition is contacted withboth an alkali metal halide and a silver compound (prior to or followingcontacting with an organophosphorus compound). Contacting of thesupported palladium composition with both an alkali metal halide and asilver compound can be carried out simultaneously; alternatively, thecontacting can be carried out sequentially in any user-desired order.

In an embodiment, one or more selectivity enhancers are contacted withthe supported palladium composition prior to contacting the compositionwith an organophosphorus compound. In such embodiments, the resultingcomposition comprising Pd/Ag, Pd/KF, or Pd/Ag/KF can be calcined underthe conditions described previously herein, and subsequently contactedwith an organophosphorus compound. For example, a phosphine oxide (PO)can be added to the Pd/Ag, Pd/KF, or Pd/Ag/KF composition to providePd/Ag/PO, Pd/KF/PO, or Pd/Ag/KF/PO composition. In an alternativeembodiment, one or more selectivity enhancers are contacted with thesupported palladium composition following contacting of the compositionwith an organophosphorus compound. For example, Ag, KF, or combinationsthereof can be added to the Pd/PO composition to provide Pd/Ag/PO,Pd/KF/PO, or Pd/Ag/KF/PO compositions. In yet another alternativeembodiment, one or more selectivity enhancers can be contacted with thepalladium supported composition and an organophosphorus compoundsimultaneously.

In an embodiment, a hydrogenation catalyst formed in accordance with themethods disclosed herein can comprise an a-alumina support, palladium,and an organophosphorus compound. In an alternative embodiment, ahydrogenation catalyst formed in accordance with the methods disclosedherein can comprise an a-alumina support, palladium, an organophosphoruscompound (for example phosphine oxide) and one or more selectivityenhancers, (for example silver, potassium fluoride, or combinationsthereof). The hydrogenation catalyst (Pd/PO, Pd/Ag/PO, Pd/KF/PO, or thePd/Ag/KF/PO compositions) can be dried to form a dried hydrogenationcatalyst. In some embodiments, this drying step can be carried out at atemperature in the range of from about 0° C. to about 150° C.;alternatively, from about 30° C. to about 100° C.; alternatively, fromabout 50° C. to about 80° C.; and for a period of from about 0.1 hour toabout 100 hours; alternatively, from about 0.5 hour to about 20 hours;alternatively, from about 1 hour to about 10 hours. In an embodiment,the organophosphorus compound can comprise an organophosphorus compoundprecursor which upon exposure to air, the temperature ranges used duringdrying of the aforementioned composition or both is converted to anorganophosphorus compound of the type described herein.

The dried hydrogenation catalyst can be reduced using hydrogen gas or ahydrogen gas containing hydrocarbon, for example the hydrocarbon streamof the process, thereby providing for optimum operation of the process.Such a gaseous hydrogen reduction can be carried out at a temperature inthe range of from, for example, about 0° C. to about 150° C.;alternatively, 10° C. to about 100° C.; alternatively, about 20° C. toabout 80° C. Additionally, or alternatively, the dried hydrogenationcatalyst can be reduced in a pressurized atmosphere and at a disclosedtemperature, such as ambient temperature for a period of about 8 toabout 24 hours.

In an embodiment, a method of preparing a hydrogenation catalyst cancomprise contacting an inorganic support with a palladium-containingcompound (for example palladium chloride, or palladium nitrate) to forma palladium supported composition; drying and calcining the palladiumsupported composition to form a dried and calcined palladium supportedcomposition. The dried and calcined palladium supported composition canthen be contacted with a silver-containing compound (for example silvernitrite, or silver fluoride) to form a Pd/Ag composition which can thenbe dried and/or calcined to form a dried and/or calcined Pd/Agcomposition. The dried and/or calcined Pd/Ag composition can becontacted with an alkali metal fluoride (for example potassium fluoride)to form a Pd/Ag/KF composition which is then dried and calcined. Thedried and calcined Pd/Ag/KF composition can then be contacted with anorganophosphorus compound (for example phosphine oxide or a precursor)to form a hydrogenation catalyst. In an alternative embodiment, thePd/Ag/KF composition can be added to an unsaturated hydrocarbon and theorganophosphorus compound can be separately added to the unsaturatedhydrocarbon so that the Pd/Ag/KF composition contacts theorganophosphorus compound to form the hydrogenation catalyst while incontact with the unsaturated hydrocarbon. The hydrogenation catalyst canbe further processed by drying the hydrogenation catalyst to form adried hydrogenation catalyst. The contacting, drying, and calcining canbe carried out using any suitable technique and conditions such as thosedescribed previously herein.

Examples of suitable hydrogenation catalysts and methods for preparationthereof are disclosed U.S. Pat. Nos. 8,6333,127, 5,489,565, 5,585,318,and 5,510,550, each of which is incorporated herein by reference in itsentirety for all purposes.

Embodiments of a hydrogenation process can include cracking a feedstream to produce a cracked gas stream comprising methylacetylene,propadiene, acetylene, ethylene, propylene, ethane, propane, methane,hydrogen, carbon monoxide, C₄ ⁺ components, or combinations thereof;fractionating the cracked gas stream into a C₂ ⁻ stream and a C₃ ⁺stream, wherein the C₂ ⁻ stream can comprise acetylene, ethylene,ethane, carbon monoxide, methane, hydrogen, carbon monoxide, orcombinations thereof, and wherein the C₃ ⁺ stream can comprise the C₃ ⁺components; hydrogenating at least a portion of the acetylene of the C₂⁻ stream in the presence of a hydrogenation catalyst to yield a productcomprising ethylene, wherein the hydrogenation catalyst has aselectivity for conversion of acetylene to ethylene of about 90 mol % orgreater based on the moles of acetylene converted to the product,wherein the hydrogenating occurs in a reaction zone under conditionscomprising a flow index (I_(F)) in a range of from about 0.09 to about35; alternatively, from about 0.27 to about 25; alternatively, fromabout 0.4 to about 20; alternatively, from about 1.0 to about 5.6,wherein the I_(F) is defined as:

${I_{F} = \frac{F \times \lbrack{CO}\rbrack}{V}},$

wherein F is the flow rate of the C₂ ⁻ stream into the reaction zone inunits of kg/h, [CO] is the concentration of carbon monoxide in the C₂ ⁻stream in units of mol %, and V is the volume of the portion of thereaction zone in units of ft³; removing ethylene from the product; andpolymerizing ethylene into one or more polymer products.

Embodiments of a hydrogenation process can also include cracking a feedstream to produce a cracked gas stream comprising methylacetylene,propadiene, acetylene, propylene, ethylene, propane, ethane, methane,hydrogen, carbon monoxide, C₄ ⁺ components (C₄ ⁺ components comprisingC₄ hydrocarbons and heavier), or combinations thereof; fractionating thecracked gas stream into a C₃ ⁻ stream and a C₄ ⁺ stream, wherein the C₃⁻ stream can comprise methylacetylene, propadiene, acetylene, propylene,ethylene, propane, ethane, carbon monoxide, methane, hydrogen, orcombinations thereof, and wherein the C₄ ⁺ stream can comprise the C₄ ⁺components; hydrogenating at least a portion of the methylacetylene,propadiene, acetylene, or a combination thereof of the C₃ ⁻ stream inthe presence of a hydrogenation catalyst to yield a product comprisingpropylene, ethylene, or both, wherein the hydrogenation catalyst has aselectivity for conversion of methylacetylene, propadiene, acetylene, ora combination thereof to propylene, ethylene, or both of about 90 mol %or greater based on the moles of methylacetylene, propadiene, acetylene,or a combination thereof converted to the product, wherein thehydrogenating step occurs in a reaction zone under conditions comprisinga flow index (I_(F)) in a range of from about 0.09 to about 35;alternatively, from about 0.27 to about 25; alternatively, from about0.4 to about 20; alternatively, from about 1.0 to about 5.6, wherein theI_(F) is defined as:

${I_{F} = \frac{F \times \lbrack{CO}\rbrack}{V}},$

wherein F is the flow rate of the C₃ ⁻ stream into the reaction zone inunits of kg/h, [CO] is the concentration of carbon monoxide in the C₃ ⁻stream in units of mol %, and V is the volume of the portion of thereaction zone in units of ft³; removing propylene, ethylene, or bothfrom the product; and polymerizing propylene, ethylene, or both into oneor more polymer products.

In embodiments of the hydrogenation process, the [CO] in the reactionzone ranges from about 0.0001 mol % to about 0.15 mol %.

In embodiments of the hydrogenation process, the highly unsaturatedhydrocarbon can comprise acetylene, wherein the unsaturated hydrocarboncan comprise ethylene. In additional or alternative embodiments of thehydrogenation process, the highly unsaturated hydrocarbon can comprisemethylacetylene, propadiene, or both; and the unsaturated hydrocarboncan comprise propylene.

In embodiments of the hydrogenation process, the reaction zone 30 cancomprise a first stage 31 and a second stage 35, wherein the first stage31 and the second stage 35 of the reaction zone 30 can comprise thehydrogenation catalyst. The first stage 31 of the reaction zone 30 andthe second stage 35 of the reaction zone 30 can be contained in a commonvessel; or the first stage 31 of the reaction zone 30 can comprise afirst reactor (or the first stage) and the second stage 35 of thereaction zone 30 can comprise a second reactor (or the second stage),wherein the first reactor (or the first stage) and the second reactor(or the second stage) are connected in series.

The hydrogenation catalyst of the hydrogenation process can comprise anembodiment of the catalyst described herein. For example, thehydrogenation catalyst can comprise palladium, an inorganic support, andoptionally, an organophosphorus compound. The hydrogenation catalyst canfurther comprise Group 1B metals, Group 1B metal compounds, silvercompounds, fluorine, fluoride compounds, sulfur, sulfur compounds,alkali metals, alkali metal compounds, alkaline earth metals, alkalineearth metal compounds, iodine, iodide compounds, or combinationsthereof. The inorganic support has a surface area of from about 2 m²/gto about 100 m²/g, and greater than about 90 wt. % of the palladium isconcentrated near a periphery of the support. The organophosphoruscompound of the hydrogenation catalyst can be: i) present in an amountof from about 0.005 wt. % to about 5 wt. % based on the total weight ofthe hydrogenation catalyst; ii) represented by the general formula(R)_(x)(OR′)_(y)P═O, wherein x and y are integers ranging from 0 to 3and x plus y equals 3, wherein each R is hydrogen, a hydrocarbyl group,or combinations thereof; and wherein each R′ is a hydrocarbyl group;iii) a product of an organophosphorus compound precursor represented bythe general formula of (R)_(x)(OR′)_(y)P, wherein x and y are integersranging from 0 to 3 and x plus y equals 3, wherein each R is hydrogen, ahydrocarbyl group, or combinations thereof; and wherein each R′ is ahydrocarbyl group; iv) a phosphine oxide, a phosphate, a phosphinate, aphosphonate, a phosphine, a phosphite, a phosphinite, a phosphonite, orcombinations thereof; or v) combinations thereof.

Additionally, or alternatively, embodiments of the disclosedhydrogenation process can also be described using FIG. 1. Thehydrogenation process can include feeding or flowing a feed via a feedstream 12 to a furnace 10; thermally cracking the feed stream in thefurnace 10 to yield a cracked gas stream 14 comprising compoundsincluding highly unsaturated hydrocarbon, saturated hydrocarbon, carbonmonoxide, or combinations thereof; flowing the cracked gas stream 14from the furnace 10 to a fractionation zone 20 (for example afractionation zone comprising a demethanizer, a deethanizer, adepropanizer, or combinations thereof), wherein the fractionation zone20 separates the cracked gas stream 14 into a hydrocarbon stream 24 (forexample a hydrocarbon stream comprising an overhead product C₂ ⁻ streamfor a frontend deethanizer, comprising an overhead product C³⁻ streamfor a frontend depropanizer, or comprising a bottoms product C₂ ⁺ streamfor a frontend demethanizer) and a stream 22 (for example a streamcomprising a bottoms product C₃ ⁺ stream for a frontend deethanizer,comprising a bottoms product C₄ ⁺ stream for a frontend depropanizer, orcomprising an overhead methane-rich stream for a frontend demethanizer);providing (via hydrocarbon stream 24) a highly unsaturated hydrocarbonand carbon monoxide to reaction zone 30 comprising a hydrogenationcatalyst; and hydrogenating the highly unsaturated hydrocarbon to yielda product comprising an unsaturated hydrocarbon in the reaction zone 30,wherein the hydrogenation catalyst has a selectivity for conversion ofthe highly unsaturated hydrocarbon to the unsaturated hydrocarbon ofabout 90 mol % or greater based on the moles of the highly unsaturatedhydrocarbon which were converted to the product, and wherein thehydrogenating step occurs under conditions comprising a flow index(I_(F)) in a range of from about 0.09 to about 35; alternatively, fromabout 0.27 to about 25; alternatively, from about 0.4 to about 20;alternatively, from about 1.0 to about 5.6, wherein the I_(F) is definedas:

${I_{F} = \frac{F \times \lbrack{CO}\rbrack}{V}},$

wherein F is flow rate of the hydrocarbon stream 24 into the reactionzone 30 in units of kg/h, [CO] is the concentration of carbon monoxidein the hydrocarbon stream 24 in units of mol %, and V is the volume ofthe portion of the reaction zone 30 in units of ft³. In embodiments ofthe hydrogenation process, the reaction zone 30 can comprise a singlestage reaction zone or a multi-stage reaction zone (for example areaction zone comprising a first stage 31 and a second stage 35).Hydrogenation in the reaction zone 30 can comprise contacting thehydrogenation catalyst with the highly unsaturated hydrocarbon in thepresence of hydrogen (for example hydrogen can be included in thehydrocarbon stream 24 or a separate supply of hydrogen can feed to thereaction zone 30 by techniques disclosed herein or known in the art withthe aid of this disclosure); or combinations thereof. Contacting thehydrogenation catalyst with the highly unsaturated hydrocarbon in thepresence of hydrogen can be conducted at a temperature less than aboutthe boiling point of a component of the hydrogenation catalyst (forexample an organophosphorus compound).

Various benefits and advantages can be achieved with the disclosedembodiments.

For example, the hydrogenation catalysts disclosed herein can be usedfor the hydrogenation of a highly unsaturated hydrocarbon at highconversions in a reaction zone without sacrificing catalyst selectivity(for example selectivity for conversion of the highly unsaturatedhydrocarbon to the unsaturated hydrocarbon can be greater than about 90mol % for all conversion embodiments). As such, the disclosedembodiments allow near 100 mol % conversion of a highly unsaturatedhydrocarbon from the hydrocarbon stream 24 in disclosed embodiments.

Moreover, embodiments of the disclosed system and process can operate atlow carbon monoxide levels (for example less than about 100 ppmv, 20 to50 ppmv) without introducing further risk of reaction instability orrunaway reaction conditions.

Additionally, embodiments of the disclosed system and process canwithstand fluctuations in the carbon monoxide concentration, forexample, if [CO] is lower than 100 ppmv at one point in time and higherat another point in time due to high amounts of carbon monoxide, forexample, in a feed stream 12 comprising a high [CO] FCC gas.

Further, it is believed that the risk of runaway reactions is low whenembodiments of the disclosed system and process operate at conditionswithin the flow index (I_(F)) range disclosed herein.

Moreover still, embodiments having or using a front-end deethanizerconfiguration can be used in processes and systems having a processstream comprising large amounts of saturated hydrocarbon (for examplecracked gas stream 14). In such processes and systems, alkynes heavierthan acetylene may not feed to the first stage 31 of the reaction zone30, and as such, first stage 31 of the reaction zone 30 operate at highconversions without the risk of runaway reactions associated withstreams of other compositions.

Additionally, the hydrogenation catalyst comprising an embodiment of theorganophosphorus compound can display an increased activity over sometime period and enhanced initial selectivity wherein theorganophosphorus compound is associated with the hydrogenation catalyst.This can be advantageous for reactions employing a fresh catalyst as theorganophosphorus compound can allow for a more stable operation and areduction in the potential for a runaway reaction due to the increase incatalyst selectivity and predictable catalytic activity as thecomposition stabilizes.

EXAMPLES

The disclosure having been generally described, the following examplesare given as particular embodiments of the disclosure and to demonstratethe practice and advantages thereof. It is understood that the examplesare given by way of illustration and are not intended to limit thespecification of the claims to follow in any manner.

In the following examples, the performance of a hydrogenation catalystwas compared at two flow indexes. A catalyst sample was prepared onα-Al₂O₃ pellets supplied by Süd Chemie, Heufeld, Germany in the form of4 mm×4 mm tablets as described in U.S. Pat. Nos. 5,489,565; 5,585,318;and 5,587,348, each of which is incorporated by reference herein in itsentirety. The α-Al₂O₃ pellets had a surface area of about 5 to about 7m²/g (determined by the BET method employing N₂).

The catalyst was evaluated by placing a 20 ml (7.06E-04 ft³) catalystsample inside a jacketed stainless steel reactor with an inside diameterof about 0.67 inches and a length of about 18 inches. The catalystresided in the middle of the reactor; both ends of the reactor werepacked with 14 grit alundum; and a 0.19 inch diameter thermowell wascentered in the catalyst bed. The reactor temperature was controlled bycirculating a heating medium containing a mixture of ethylene glycol andwater through the jacket of the reactor. The catalyst was first reducedat a catalyst bed temperature of about 100° F. (about 37.8° C.) to 200°F. (about 93.3° C.) for about 1 hour under hydrogen gas flowing at 200ml/min at 200 pounds per square inch gauge (psig). The catalyst bed wasthen cooled to a temperature below the anticipated T1 temperature. Ifthe T1 temperature was not known, the catalyst bed was cooled to atemperature about 75° F. (about 23.9° C.) to about 85° F. (about 29.4°C.). Thereafter, a hydrocarbon stream was continuously introduced to thereactor at a flow rate of 900 ml/min (0.040 kg/hr) at 200 psig. Thecomposition of the hydrocarbon stream was prepared by adding the statedamounts of carbon monoxide catalyst to a hydrocarbon stream having thecomposition of Table 2. The hydrocarbon stream composition of Table 2 istypical of a hydrocarbon feed from the top of a deethanizerfractionation tower in an ethylene plant.

TABLE 2 Reactor Feed Component mol % Hydrogen 26.63 Methane 25.81Acetylene 0.16 Ethylene 47.36

While the hydrocarbon stream was passing over the catalyst the effluentwas regularly sampled and analyzed by gas chromatography. The catalystbed temperature was determined by inserting a thermocouple into thethermowell and varying its position to determine the highest temperaturefor the catalyst bed. Then the reactor jacket temperature was raised afew degrees, and the testing cycle was repeated until the acetyleneconcentration in the effluent dropped below 20 ppm. The testing cyclecontinued until 3 weight % of ethane was measured in the effluent. Thecleanup temperature, T1, is defined as the temperature at which theacetylene concentration drops below 20 ppm. The T2, or runawaytemperature, is defined as the temperature at which 3 wt% of ethane isproduced. At this temperature, the uncontrolled hydrogenation ofethylene to ethane may occur. The delta T (ΔT) is the difference betweenT2 and T1. This value can be viewed as a measure of the selectivity ofthe hydrogenation catalyst or even a window of operability.

TABLE 3 Flow Index (I_(F)) [CO] [(kg mol %)/ T1 T2 ΔT Test (mol %) (hrft³)] (° F.) (° F.) (° F.) Notes 1 0.034 1.912 112 176 64 NormalOperations 2 0.0005 0.028 * * * * Run Away prior to reaching T1

The temperature T1 in Test 1 of 112° F. is about 44.4° C. Thetemperature T2 in Test 1 of 176° F. is about 80.0° C. The temperature ΔTin Test 1 of 64° F. is about 17.8° C.

During the selective hydrogenation experiment with a Flow index of 1.912the process performed consistently and predictably with a good window ofoperations as determined by the ΔT. However, under Test 2 at a flowindex at 0.028, the hydrogenation process was not controllable and a T1was not measurable. At these conditions, the hydrogenation reaction ranaway at little more than room temperature.

Additional Description

Embodiments of a system and process have been described. The followingare a first set of nonlimiting, specific embodiments in accordance withthe present disclosure:

A first embodiment, which is a process comprising:

hydrogenating, in a reaction zone, a highly unsaturated hydrocarbonreceived from a hydrocarbon stream to yield a product comprising anunsaturated hydrocarbon, wherein the hydrogenating step occurs in thepresence of a hydrogenation catalyst which has a selectivity forconversion of the highly unsaturated hydrocarbon to the unsaturatedhydrocarbon of about 90 mol % or greater based on the moles of thehighly unsaturated hydrocarbon which are converted to the product,

wherein the hydrogenating step occurs in a reaction zone underconditions comprising a flow index (I_(F)) in a range of about 0.09 toabout 35, wherein the I_(F) is defined as:

${I_{F} = \frac{F \times \lbrack{CO}\rbrack}{V}},$

wherein F is the flow rate of the hydrocarbon stream into the reactionzone in units of kg/h, [CO] is the concentration of carbon monoxide inthe hydrocarbon stream in units of mol %, and V is the volume of thereaction zone in units of ft³.

A second embodiment, which is the process of the first embodiment,wherein the selectivity is defined as:

$S = {100 \times \left( \frac{{{UH}(p)} - {{UH}(f)}}{{{HUH}(f)} - {{HUH}(p)}} \right)}$

where S is selectivity in mol %, UH(p) is moles of the unsaturatedhydrocarbon in the product, UH(f) is moles of the unsaturatedhydrocarbon in the hydrocarbon stream, HUH(f) is the moles of highlyunsaturated hydrocarbon in the hydrocarbon stream, and HUH(p) is themoles of the highly unsaturated hydrocarbon in the product.

A third embodiment, which is the process of any of the first through thesecond embodiments, wherein the highly unsaturated hydrocarbon comprisesacetylene, and wherein the unsaturated hydrocarbon comprises ethylene.

A fourth embodiment, which is the process of any of the first throughthe third embodiments, wherein the highly unsaturated hydrocarboncomprises methylacetylene, propadiene, or both; and wherein theunsaturated hydrocarbon comprises propylene.

A fifth embodiment, which is the process of any of the first through thefourth embodiments, further comprising:

cracking a feed stream to produce a cracked gas stream comprising thehighly unsaturated hydrocarbon, carbon monoxide, and a saturatedhydrocarbon.

A sixth embodiment, which is the process of the fifth embodiment,further comprising:

fractionating the cracked gas stream to yield a C₃ ⁻ stream or a C₂ ⁻stream comprising the highly unsaturated hydrocarbon, carbon monoxide,and about 90 mol % or greater of the saturated hydrocarbon contained inthe cracked gas stream, wherein at least a portion of the highlyunsaturated hydrocarbon in the C₃ ⁻ stream or the C₂ ⁻ stream ishydrogenated in the presence of the hydrogenation catalyst.

A seventh embodiment, which is the process of any of the first throughthe sixth embodiments, wherein the [CO] in the reaction zone is fromabout 0.0001 mol % to about 0.15 mol %.

An eighth embodiment, which is the process of any of the first throughthe seventh embodiments, wherein the hydrogenating step comprises:

contacting the hydrogenation catalyst with at least a portion of thehighly unsaturated hydrocarbon in the presence of hydrogen.

A ninth embodiment, which is the process of any of the first through theeighth embodiments, wherein the reaction zone comprises a first stageand a second stage, wherein at least one of the first stage and thesecond stage of the reaction zone contains the hydrogenation catalyst.

A tenth embodiment, which is the process of the ninth embodiment,wherein:

i) the first stage of the reaction zone and the second stage of thereaction zone are contained in a common vessel; or

ii) the first stage of the reaction zone is a first reactor, the secondstage of the reaction zone is a second reactor, and the first reactorand the second reactor are connected in series.

An eleventh embodiment, which is the process of any of the first throughthe tenth embodiments, wherein the hydrogenation catalyst comprisespalladium, an inorganic support, and optionally, an organophosphoruscompound.

A twelfth embodiment, which is the process of the eleventh embodiment,wherein the hydrogenation catalyst further comprises Group 1B metals,Group 1B metal compounds, silver compounds, fluorine, fluoridecompounds, sulfur, sulfur compounds, alkali metals, alkali metalcompounds, alkaline earth metals, alkaline earth metal compounds,iodine, iodide compounds, or combinations thereof.

A thirteenth embodiment, which is the process of any of the elevenththrough the twelfth embodiments, wherein the inorganic support has asurface area of from about 2 m²/g to about 100 m²/g, and greater thanabout 90 wt. % of the palladium is concentrated near a periphery of theof the inorganic support.

A fourteenth embodiment, which is the process of any of the elevenththrough the thirteenth embodiments, wherein the organophosphoruscompound of the hydrogenation catalyst is:

i) present in an amount of from about 0.005 wt. % to about 5 wt. % basedon the total weight of the hydrogenation catalyst;

ii) represented by a general formula (R)_(x)(OR′)_(y)P═O, wherein x andy are integers ranging from 0 to 3 and x plus y equals 3, wherein each Ris hydrogen, a hydrocarbyl group, or combinations thereof; and whereineach R′ is a hydrocarbyl group;

iii) a product of an organophosphorus compound precursor represented bythe general formula of (R)_(x)(OR′)_(y)P, wherein x and y are integersranging from 0 to 3 and x plus y equals 3, wherein each R is hydrogen, ahydrocarbyl group, or combinations thereof; and wherein each R′ is ahydrocarbyl group;

iv) a phosphine oxide, a phosphate, a phosphinate, a phosphonate, aphosphine, a phosphite, a phosphinite, a phosphonite, or combinationsthereof; or

v) combinations thereof.

A fifteenth embodiment, which is a system comprising: a hydrocarbonstream comprising a highly unsaturated hydrocarbon and carbon monoxide;and

a reaction zone receiving the hydrocarbon stream, wherein the reactionzone contains at least one hydrogenation catalyst, wherein the highlyunsaturated hydrocarbon is hydrogenated in the reaction zone to yield aproduct comprising an unsaturated hydrocarbon, wherein the at least onehydrogenation catalyst has a selectivity for conversion of the highlyunsaturated hydrocarbon to the unsaturated hydrocarbon of about 90 mol %or greater based on the moles of the highly unsaturated hydrocarbonwhich are converted to the product, wherein the reaction zone comprisesa flow index (I_(F)) in a range of about 0.09 to about 35, wherein theI_(F) is defined as:

${I_{F} = \frac{F \times \lbrack{CO}\rbrack}{V}},$

wherein F is the flow rate of the hydrocarbon stream into the reactionzone in units of kg/h, [CO] is the concentration of carbon monoxide inthe hydrocarbon stream in units of mol %, and V is the volume of theportion of the reaction zone in units of ft³.

A sixteenth embodiment, which is the system of the fifteenth embodiment,wherein the selectivity is defined as:

$S = {100 \times \left( \frac{{{UH}(p)} - {{UH}(f)}}{{{HUH}(f)} - {{HUH}(p)}} \right)}$

where S is the selectivity in mol %, UH(p) is moles of the unsaturatedhydrocarbon in the product, UH(f) is moles of the unsaturatedhydrocarbon in the hydrocarbon stream, HUH(f) is the moles of highlyunsaturated hydrocarbon in the hydrocarbon stream, and HUH(p) is themoles of the highly unsaturated hydrocarbon in the product.

A seventeenth embodiment, which is the system of any of the fifteenththrough the sixteenth embodiments, further comprising:

a tube in a furnace fluidly connected to and upstream of the reactionzone, wherein at least a portion of the tube is made of a co-productionmetal; and

a cracked gas stream comprising the highly unsaturated hydrocarbon, asaturated hydrocarbon, and carbon monoxide flowing from the tube.

An eighteenth embodiment, which is the system of the seventeenthembodiment, further comprising:

a fractionation zone comprising a deethanizer or a depropanizer fluidlyconnected to and upstream of the reaction zone, wherein thefractionation zone fractionates the cracked gas stream into an overheadproduct and a bottoms product, wherein the overhead product comprisesthe highly unsaturated hydrocarbon, carbon monoxide, and about 90 mol %or greater of the saturated hydrocarbon contained in the cracked gasstream, wherein the overhead product flows to the reaction zone from thefractionation zone via the hydrocarbon stream.

A nineteenth embodiment, which is the system of any of the seventeenththrough the eighteenth embodiments, further comprising:

wherein the co-production metal comprises chromed steel, aluminizedsteel, or both.

A twentieth embodiment, which is the system of the nineteenthembodiment, wherein:

i) the chromed steel is a steel coated with chromium;

ii) the aluminized steel is a steel coated with aluminum;

iii) the chromed steel is an alloy comprising chromium and a steel;

iv) the aluminized steel is an alloy comprising aluminum and a steel; or

v) combinations thereof.

A twenty-first embodiment, which is the system of any of the fifteenththrough the twentieth embodiments, wherein the [CO] in the reaction zoneis from about 0.0001 mol % to about 0.15 mol %.

A twenty-second embodiment, which is the system of any of the fifteenththrough the twenty-first embodiments, wherein the reaction zonecomprises a first stage and a second stage, wherein the first stage, thesecond stage, or both contains the at least one hydrogenation catalyst.

A twenty-third embodiment, which is the system of the twenty-secondembodiment, wherein:

i) the first stage of the reaction zone is a first reactor, wherein thesecond stage of the reaction zone is a second reactor; or

ii) the first stage of the reaction zone and the second stage of thereaction zone are contained in a common vessel.

A twenty-fourth embodiment, which is the system of any of the fifteenththrough the twenty-third embodiments, wherein the highly unsaturatedhydrocarbon comprises acetylene, wherein the unsaturated hydrocarboncomprises ethylene.

A twenty-fifth embodiment, which is the system of any of the fifteenththrough the twenty-fourth embodiments, wherein the highly unsaturatedhydrocarbon comprises methylacetylene, propadiene, or both; and whereinthe unsaturated hydrocarbon comprises propylene.

A twenty-sixth embodiment, which is the system of any of the fifteenththrough the twenty-fifth embodiments, wherein the hydrogenation catalystcomprises palladium, an inorganic support, and optionally, anorganophosphorus compound.

A twenty-seventh embodiment, which is the system of the twenty-sixthembodiment, wherein the hydrogenation catalyst further comprises Group1B metals, Group 1B metal compounds, silver compounds, fluorine,fluoride compounds, sulfur, sulfur compounds, alkali metals, alkalimetal compounds, alkaline earth metals, alkaline earth metal compounds,iodine, iodide compounds, or combinations thereof.

A twenty-eighth embodiment, which is the system of any of thetwenty-sixth through the twenty-seventh embodiments, wherein theinorganic support has a surface area of from about 2 m²/g to about 100m²/g, and greater than about 90 wt. % of the palladium is concentratednear a periphery of the inorganic support.

A twenty-ninth embodiment, which is the system of any of thetwenty-sixth through the twenty-eighth embodiments, wherein theorganophosphorus compound of the hydrogenation catalyst is:

i) present in an amount of from about 0.005 wt. % to about 5 wt. % basedon the total weight of the hydrogenation catalyst;

ii) represented by a general formula (R)_(x)(OR′)_(y)P═O, wherein x andy are integers ranging from 0 to 3 and x plus y equals 3, wherein each Ris hydrogen, a hydrocarbyl group, or combinations thereof; and whereineach R′ is a hydrocarbyl group;

iii) a product of an organophosphorus compound precursor represented bythe general formula of (R)_(x)(OR′)_(y)P, wherein x and y are integersranging from 0 to 3 and x plus y equals 3, wherein each R is hydrogen, ahydrocarbyl group, or combinations thereof; and wherein each R′ is ahydrocarbyl group;

iv) a phosphine oxide, a phosphate, a phosphinate, a phosphonate, aphosphine, a phosphite, a phosphinite, a phosphonite, or combinationsthereof; or

v) combinations thereof.

A thirtieth embodiment, which is a system comprising:

a furnace comprising at least one tube comprising a co-production metal;

a cracked gas stream comprising a highly unsaturated hydrocarbon, asaturated hydrocarbon, and carbon monoxide flowing from the at least onetube;

a fractionation zone comprising a deethanizer or a depropanizer, whereinthe fractionation zone fractionates the cracked gas stream into anoverhead product and a bottoms product, wherein the overhead productcomprises the highly unsaturated hydrocarbon, carbon monoxide, and about90 mol % or greater of the saturated hydrocarbon contained in thecracked gas stream;

a hydrocarbon stream comprising the overhead product flowing from thefractionation zone; and

a reaction zone receiving the hydrocarbon stream, wherein the reactionzone comprises at least one hydrogenation catalyst, wherein, in thereaction zone, the highly unsaturated hydrocarbon is hydrogenated toyield a product comprising an unsaturated hydrocarbon in the reactionzone, wherein the reaction zone comprises a flow index (I_(F)) in arange of about 0.09 to about 35, wherein the I_(F) is defined as:

${I_{F} = \frac{F \times \lbrack{CO}\rbrack}{V}},$

wherein F is the flow rate of the hydrocarbon stream into the reactionzone in units of kg/h, [CO] is the concentration of carbon monoxide inthe hydrocarbon stream in units of mol %, and V is the volume of theportion of the reaction zone in units of ft³.

A thirty-first embodiment, which is the system of the thirtiethembodiment, wherein the co-production metal comprises chromed steel,aluminized steel, or both.

A thirty-second embodiment, which is the system of the thirty-firstembodiment, wherein:

i) the chromed steel is a steel coated with chromium;

ii) the aluminized steel is a steel coated with aluminum;

iii) the chromed steel is an alloy comprising chromium and a steel;

iv) the aluminized steel is an alloy comprising aluminum and a steel; or

v) combinations thereof.

A thirty-third embodiment, which is the system of any of the thirtieththrough the thirty-second embodiments, wherein the at least onehydrogenation catalyst has a selectivity for conversion of the highlyunsaturated hydrocarbon to the unsaturated hydrocarbon of about 90 mol %or greater based on the moles of the highly unsaturated hydrocarbonwhich are converted to the product, wherein the selectivity is definedas:

$S = {100 \times \left( \frac{{{UH}(p)} - {{UH}(f)}}{{{HUH}(f)} - {{HUH}(p)}} \right)}$

where S is the selectivity in mol %, UH(p) is moles of the unsaturatedhydrocarbon in the product, UH(f) is moles of the unsaturatedhydrocarbon in the hydrocarbon stream, HUH(f) is the moles of highlyunsaturated hydrocarbon in the hydrocarbon stream, and HUH(p) is themoles of the highly unsaturated hydrocarbon in the product.

A thirty-fourth embodiment, which is the system of the thirty-thirdembodiment, wherein the at least one hydrogenation catalyst comprisespalladium, an inorganic support, and optionally, an organophosphoruscompound.

A thirty-fifth embodiment, which is the system of the thirty-fourthembodiment, wherein the organophosphorus compound of the hydrogenationcatalyst is:

i) present in an amount of from about 0.005 wt. % to about 5 wt. % basedon the total weight of the hydrogenation catalyst;

ii) represented by a general formula (R)_(x)(OR′)_(y)P═O, wherein x andy are integers ranging from 0 to 3 and x plus y equals 3, wherein each Ris hydrogen, a hydrocarbyl group, or combinations thereof; and whereineach R′ is a hydrocarbyl group;

iii) a product of an organophosphorus compound precursor represented bythe general formula of (R)_(x)(OR′)_(y)P, wherein x and y are integersranging from 0 to 3 and x plus y equals 3, wherein each R is hydrogen, ahydrocarbyl group, or combinations thereof; and wherein each R′ is ahydrocarbyl group;

iv) a phosphine oxide, a phosphate, a phosphinate, a phosphonate, aphosphine, a phosphite, a phosphinite, a phosphonite, or combinationsthereof; or

v) combinations thereof.

A thirty-sixth embodiment, which is the system of any of the thirtieththrough the thirty-fifth embodiments, wherein the [CO] in the reactionzone is from about 0.0001 mol % to about 0.15 mol %.

A thirty-seventh embodiment, which is a process comprising:

cracking a feed stream to produce a cracked gas stream comprisingacetylene, ethylene, ethane, methane, hydrogen, carbon monoxide, and C₃⁺ components;

fractionating the cracked gas stream into a C₂ ⁻ stream and a C₃ ⁺stream, wherein the C₂ ⁻ stream comprises acetylene, ethylene, ethane,methane, carbon monoxide, and hydrogen, wherein the C₃ ⁺ streamcomprises the C₃ ⁺ components;

hydrogenating at least a portion of the acetylene of the C₂ ⁻ stream inthe presence of a hydrogenation catalyst to yield a product comprisingethylene, wherein the hydrogenation catalyst has a selectivity forconversion of acetylene to ethylene of about 90 mol % or greater basedon the moles of acetylene which are converted to the product, whereinthe hydrogenating step occurs in a reaction zone under conditionscomprising a flow index (I_(F)) in a range of about 0.09 to about 35,wherein the I_(F) is defined as:

${I_{F} = \frac{F \times \lbrack{CO}\rbrack}{V}},$

wherein F is the flow rate of the C₂ ⁻ stream into the reaction zone inunits of kg/h, [CO] is the concentration of carbon monoxide in the C₂ ⁻stream in units of mol %, and V is the volume of the portion of thereaction zone in units of ft³;

removing ethylene from the product; and

polymerizing ethylene into one or more polymer products.

A thirty-eighth embodiment, which is the process of the thirty-seventhembodiment, wherein the selectivity is defined as:

$S = {100 \times \left( \frac{{{UH}(p)} - {{UH}(f)}}{{{HUH}(f)} - {{HUH}(p)}} \right)}$

where S is the selectivity in mol %, UH(p) is moles of ethylene in theproduct, UH(f) is moles of ethylene in the hydrocarbon stream, HUH(f) isthe moles of acetylene in the hydrocarbon stream, and HUH(p) is themoles of acetylene in the product.

A thirty-ninth embodiment, which is a process comprising:

providing a hydrocarbon stream comprising a highly unsaturatedhydrocarbon and carbon monoxide to a reaction zone comprising ahydrogenation catalyst; and

hydrogenating, in the reaction zone, the highly unsaturated hydrocarbonto yield a product comprising an unsaturated hydrocarbon, wherein thehydrogenation catalyst has a selectivity for conversion of the highlyunsaturated hydrocarbon to the unsaturated hydrocarbon of about 90 mol %or greater based on moles of the highly unsaturated hydrocarbon whichare converted to the product, wherein the hydrogenating step occursunder conditions comprising a flow index (I_(F)) in a range of about0.09 to about 35, wherein the I_(F) is defined as:

${I_{F} = \frac{F \times \lbrack{CO}\rbrack}{V}},$

wherein F is the flow rate of the hydrocarbon stream into the reactionzone in units of kg/h, [CO] is the concentration of carbon monoxide inthe hydrocarbon stream in units of mol %, and V is the volume of theportion of the reaction zone in units of ft³.

A fortieth embodiment, which is the process of the thirty-ninthembodiment, wherein the selectivity is defined as:

$S = {100 \times \left( \frac{{{UH}(p)} - {{UH}(f)}}{{{HUH}(f)} - {{HUH}(p)}} \right)}$

where S is the selectivity in mol %, UH(p) is moles of the unsaturatedhydrocarbon in the product, UH(f) is moles of the unsaturatedhydrocarbon in the hydrocarbon stream, HUH(f) is the moles of highlyunsaturated hydrocarbon in the hydrocarbon stream, and HUH(p) is themoles of the highly unsaturated hydrocarbon in the product.

While embodiments of the invention have been shown and described,modifications thereof can be made by one skilled in the art withoutdeparting from the spirit and teachings of the invention. Theembodiments described herein are exemplary only, and are not intended tobe limiting. Many variations and modifications of the inventiondisclosed herein are possible and are within the scope of the invention.Where numerical ranges or limitations are expressly stated, such expressranges or limitations should be understood to include iterative rangesor limitations of like magnitude falling within the expressly statedranges or limitations (for example from about 1 to about 10 includes, 2,3, 4, etc.; greater than 0.10 includes 0.11, 0.12, 0.13, etc.). Use ofthe term “optionally” with respect to any element of a claim is intendedto mean that the subject element is required, or alternatively, is notrequired. Both alternatives are intended to be within the scope of theclaim. Use of broader terms such as comprises, includes, having, etc.should be understood to provide support for narrower terms such asconsisting of, consisting essentially of, comprised substantially of,etc.

Accordingly, the scope of protection is not limited by the descriptionset out above but is only limited by the claims which follow, that scopeincluding all equivalents of the subject matter of the claims. Each andevery claim is incorporated into the specification as an embodiment ofthe present invention. Thus, the claims are a further description andare an addition to the embodiments of the present invention. Thedisclosures of all patents, patent applications, and publications citedherein are hereby incorporated by reference, to the extent that theyprovide exemplary, procedural or other details supplementary to thoseset forth herein.

What is claimed is:
 1. A process comprising: hydrogenating, in areaction zone, a highly unsaturated hydrocarbon received from ahydrocarbon stream to yield a product comprising an unsaturatedhydrocarbon, wherein the hydrogenating occurs in the presence of ahydrogenation catalyst which has a selectivity for conversion of thehighly unsaturated hydrocarbon to the unsaturated hydrocarbon of about90 mol % or greater based on the moles of the highly unsaturatedhydrocarbon which are converted to the product, wherein the highlyunsaturated hydrocarbon comprises acetylene, and wherein the unsaturatedhydrocarbon comprises ethylene, and wherein the hydrogenation catalystfurther comprises one or more inorganic supports, and wherein thehydrogenating in the reaction zone occurs under conditions comprising aflow index (I_(F)) in a range of about 0.09 to about 35, wherein theI_(F) is defined as: ${I_{F} = \frac{F \times \lbrack{CO}\rbrack}{V}},$wherein F is the flow rate of the hydrocarbon stream into the reactionzone in units of kg/h, [CO] is the concentration of carbon monoxide inthe hydrocarbon stream in units of mol %, and V is the volume of thereaction zone in units of ft³.
 2. The process of claim 1 wherein thehydrogenation catalyst further comprises palladium.
 3. The process ofclaim 1 wherein the hydrogenation catalyst further comprises phosphorus.4. The process of claim 1 wherein the hydrogenation catalyst furthercomprises one or more phosphorus compounds.
 5. The process of claim 1wherein the hydrogenation catalyst further comprises a Group 1B metal.6. The process of claim 1 wherein the hydrogenation catalyst furthercomprises silver.
 7. The process of claim 1 wherein the hydrogenationcatalyst further comprises fluorine.
 8. The process of claim 1 whereinthe hydrogenation catalyst further comprises or one or more fluoridecompounds.
 9. The process of claim 1 wherein the hydrogenation catalystfurther comprises sulfur.
 10. The process of claim 1 wherein thehydrogenation catalyst further comprises or one or more sulfurcompounds.
 11. The process of claim 1 wherein the hydrogenation catalystfurther comprises one or more alkali metals.
 12. The process of claim 1wherein the hydrogenation catalyst further comprises one or morealkaline earth metals.
 13. The process of claim 1 wherein thehydrogenation catalyst further comprises iodine.
 14. The process ofclaim 4, wherein the phosphorus compound is an organophosphoruscompound.
 15. The process of claim 2, wherein the palladium isconcentrated near the periphery of the catalyst and forms a palladiumskin, wherein the skin has a thickness of from about 1 micron to about3000 microns.
 16. The process of claim 2, wherein the palladium is addedby contacting the hydrogenation with an acidic solution comprisingpalladium.
 17. The process of claim 14, wherein the organophosphoruscompound comprises a methylphosphonate, a trifluorophosphate, orcombinations thereof.
 18. The process of claim 8, wherein the fluoridecompound comprises a trifluoromethanesulfonate, a tetrafluoroborate, atrifluoromethylsulfonyl, a pentafluoroethyl, a trifluoromethylsulfonyl,or combinations thereof.
 19. The process of claim 10, wherein the sulfurcompound comprises an ethylsulfate, a methylsulfate, an octylsulfate, orcombinations thereof.
 20. The process of claim 1, wherein theselectivity is defined as:$S = {100 \times \left( \frac{{{UH}(p)} - {{UH}(f)}}{{{HUH}(f)} - {{HUH}(p)}} \right)}$where S is selectivity in mol %, UH(p) is moles of the unsaturatedhydrocarbon in the product, UH(f) is moles of the unsaturatedhydrocarbon in the hydrocarbon stream, HUH(f) is the moles of highlyunsaturated hydrocarbon in the hydrocarbon stream, and HUH(p) is themoles of the highly unsaturated hydrocarbon in the product, wherein thereaction zone comprises a first stage and a second stage, and whereinthe selectivity achieved in the first stage is greater than theselectivity achieved in the second stage.
 21. The process of claim 1,further comprising: cracking a feed stream to produce a cracked gasstream comprising the highly unsaturated hydrocarbon, carbon monoxide,and a saturated hydrocarbon.
 22. The process of claim 21, furthercomprising: fractionating the cracked gas stream to yield a C₃ ⁻ streamor a C₂ ⁻ stream comprising the highly unsaturated hydrocarbon, carbonmonoxide, and about 90 mol % or greater of the saturated hydrocarboncontained in the cracked gas stream, wherein at least a portion of thehighly unsaturated hydrocarbon in the C₃ ⁻ stream or the C₂ ⁻ stream ishydrogenated in the presence of the hydrogenation catalyst.
 23. Theprocess of claim 1, wherein the [CO] in the reaction zone is from about0.0001 mol % to about 0.15 mol %.
 24. The process of claim 20, wherein:i) the first stage of the reaction zone and the second stage of thereaction zone are contained in a common vessel; or ii) the first stageof the reaction zone is a first reactor, the second stage of thereaction zone is a second reactor, and the first reactor and the secondreactor are connected in series.
 25. A process comprising:hydrogenating, in a reaction zone, a highly unsaturated hydrocarbonreceived from a hydrocarbon stream to yield a product comprising anunsaturated hydrocarbon, wherein the hydrogenating occurs in thepresence of a hydrogenation catalyst which has a selectivity forconversion of the highly unsaturated hydrocarbon to the unsaturatedhydrocarbon of about 90 mol % or greater based on the moles of thehighly unsaturated hydrocarbon which are converted to the product, andwherein the hydrogenating in the reaction zone occurs under conditionscomprising a flow index (I_(F)) in a range of about 0.09 to about 35,wherein the I_(F) is defined as:${I_{F} = \frac{F \times \lbrack{CO}\rbrack}{V}},$ wherein F is the flowrate of the hydrocarbon stream into the reaction zone in units of kg/h,[CO] is the concentration of carbon monoxide in the hydrocarbon streamin units of mol %, and V is the volume of the reaction zone in units offt³, and wherein the process comprises a first reactor and a secondreactor in series, wherein a first effluent stream entering the firstreactor enters at a first temperature, wherein the first temperature isfrom about 100° F. and about 250° F., and a second effluent streamenters the second reactor at a second temperature, wherein the secondtemperature is from about 110° F. to about 260° F.
 26. The process ofclaim 25, wherein the selectivity is defined as:$S = {100 \times \left( \frac{{{UH}(p)} - {{UH}(f)}}{{{HUH}(f)} - {{HUH}(p)}} \right)}$where S is selectivity in mol %, UH(p) is moles of the unsaturatedhydrocarbon in the product, UH(f) is moles of the unsaturatedhydrocarbon in the hydrocarbon stream, HUH(f) is the moles of highlyunsaturated hydrocarbon in the hydrocarbon stream, and HUH(p) is themoles of the highly unsaturated hydrocarbon in the product; and whereinthe selectivity achieved in the second reactor is less than theselectivity achieved in the first reactor.
 27. The process of claim 25further comprising: cracking a feed stream to produce a cracked gasstream comprising the highly unsaturated hydrocarbon, carbon monoxide,and a saturated hydrocarbon.
 28. The process of claim 27, furthercomprising: fractionating the cracked gas stream to yield a C₃ ⁻ streamor a C₂ ⁻ stream comprising the highly unsaturated hydrocarbon, carbonmonoxide, and about 90 mol % or greater of the saturated hydrocarboncontained in the cracked gas stream, wherein at least a portion of thehighly unsaturated hydrocarbon in the C₃ ⁻ stream or the C₂ ⁻ stream ishydrogenated in the presence of the hydrogenation catalyst.
 29. Theprocess of claim 25, wherein the [CO] in the reaction zone is from about0.0001 mol % to about 0.15 mol %.
 30. A process comprising:hydrogenating, in a reaction zone, a highly unsaturated hydrocarbonreceived from a hydrocarbon stream to yield a product comprising anunsaturated hydrocarbon, wherein the hydrogenating occurs in thepresence of a hydrogenation catalyst which has a selectivity forconversion of the highly unsaturated hydrocarbon to the unsaturatedhydrocarbon of about 90 mol % or greater based on the moles of thehighly unsaturated hydrocarbon which are converted to the product, andwherein the hydrogenating in the reaction zone occurs under conditionscomprising a flow index (I_(F)) in a range of about 0.09 to about 35,wherein the I_(F) is defined as:${I_{F} = \frac{F \times \lbrack{CO}\rbrack}{V}},$ wherein F is the flowrate of the hydrocarbon stream into the reaction zone in units of kg/h,[CO] is the concentration of carbon monoxide in the hydrocarbon streamin units of mol %, and V is the volume of the reaction zone in units offt³, and wherein the process comprises a first reactor and a secondreactor in series, wherein the first reactor operates at a firsttemperature of from about 100° F. and about 250° F., and the secondreactor operates at a second temperature of from about 110° F. to about260° F.
 31. The process of claim 30, wherein the selectivity is definedas:$S = {100 \times \left( \frac{{{UH}(p)} - {{UH}(f)}}{{{HUH}(f)} - {{HUH}(p)}} \right)}$where S is selectivity in mol %, UH(p) is moles of the unsaturatedhydrocarbon in the product, UH(f) is moles of the unsaturatedhydrocarbon in the hydrocarbon stream, HUH(f) is the moles of highlyunsaturated hydrocarbon in the hydrocarbon stream, and HUH(p) is themoles of the highly unsaturated hydrocarbon in the product; and whereinthe selectivity achieved in the second reactor is less than theselectivity achieved in the first reactor.
 32. The process of claim 30,further comprising: cracking a feed stream to produce a cracked gasstream comprising the highly unsaturated hydrocarbon, carbon monoxide,and a saturated hydrocarbon.
 33. The process of claim 32, furthercomprising: fractionating the cracked gas stream to yield a C₃ ⁻ streamor a C₂ ⁻ stream comprising the highly unsaturated hydrocarbon, carbonmonoxide, and about 90 mol % or greater of the saturated hydrocarboncontained in the cracked gas stream, wherein at least a portion of thehighly unsaturated hydrocarbon in the C₃ ⁻ stream or the C₂ ⁻ stream ishydrogenated in the presence of the hydrogenation catalyst.
 34. Theprocess of claim 30, wherein the [CO] in the reaction zone is from about0.0001 mol % to about 0.15 mol %.